U.S. patent application number 10/062005 was filed with the patent office on 2002-10-03 for deposition apparatus and deposition method.
Invention is credited to Mizukami, Mayumi, Seo, Satoshi, Yamazaki, Shunpei.
Application Number | 20020139303 10/062005 |
Document ID | / |
Family ID | 18891043 |
Filed Date | 2002-10-03 |
United States Patent
Application |
20020139303 |
Kind Code |
A1 |
Yamazaki, Shunpei ; et
al. |
October 3, 2002 |
Deposition apparatus and deposition method
Abstract
A deposition apparatus is provided for manufacturing an organic
compound layer having a plurality of function regions. The
deposition apparatus includes a plurality of evaporation sources
within a deposition chamber, for enabling continuous formation of
respective function regions comprised of organic compounds and,
further, formation of a mixed region at an interface between
adjacent ones of the function regions. With the deposition
apparatus having such fabrication chamber, it is possible to
prevent impurity contamination between the functions regions and
further possible to form an organic compound layer with an energy
gap relaxed at the interface.
Inventors: |
Yamazaki, Shunpei; (Tokyo,
JP) ; Seo, Satoshi; (Kanagawa, JP) ; Mizukami,
Mayumi; (Tokyo, JP) |
Correspondence
Address: |
FISH & RICHARDSON, PC
4350 LA JOLLA VILLAGE DRIVE
SUITE 500
SAN DIEGO
CA
92122
US
|
Family ID: |
18891043 |
Appl. No.: |
10/062005 |
Filed: |
January 31, 2002 |
Current U.S.
Class: |
118/719 ;
118/726; 427/255.6 |
Current CPC
Class: |
H01L 51/5068 20130101;
H05B 33/12 20130101; C23C 14/564 20130101; H01L 33/08 20130101;
B05D 1/60 20130101; C23C 14/12 20130101; H01L 51/5008 20130101;
H01L 33/36 20130101; H01L 2924/0002 20130101; H05B 33/02 20130101;
H01L 51/5036 20130101; H01L 51/001 20130101; C23C 14/568 20130101;
H01L 51/5203 20130101; H01L 2924/0002 20130101; H01L 2924/00
20130101; H01L 51/5012 20130101 |
Class at
Publication: |
118/719 ;
427/255.6; 118/726 |
International
Class: |
C23C 016/00; B05D
005/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 1, 2001 |
JP |
2001-26184 |
Claims
What is claimed is:
1. A deposition apparatus comprising: a plurality of deposition
chambers; and a plurality of evaporation sources in said deposition
chambers; wherein each of the plurality of evaporation sources
comprises at least one organic compound having a different
function, and wherein the organic compounds having the different
functions are continuously deposited by a vacuum evaporation from
said plurality of evaporation sources.
2. A deposition apparatus according to claim 1, wherein the
deposition apparatus comprises: a first deposition chamber forming
a first organic compound layer, a second deposition chamber forming
a second organic compound layer, and a third deposition chamber
forming a third organic compound layer.
3. A deposition apparatus according to claim 2, wherein: said first
organic compound layer emits a red light, said second organic
compound layer emits a green light, and said third organic compound
layer emits a blue light.
4. A deposition apparatus according to claim 1, wherein each said
evaporation source has an organic compound selected from the group
consisting of a hole injectability, hole transportability,
luminescent ability, blocking ability, electron transportability,
or electron injectability.
5. A deposition apparatus comprising: a plurality of deposition
chambers; and a plurality of evaporation sources in said deposition
chambers; wherein each of the plurality of evaporating sources
comprises at least one organic compound having a different
function, and wherein at least two of the organic compounds having
the different functions are simultaneously deposited by a vacuum
evaporation from said plurality of evaporation sources.
6. A deposition apparatus according to claim 5, wherein the
deposition apparatus comprises: a first deposition chamber forming
a first organic compound layer, a second deposition chamber forming
a second organic compound layer, and a third deposition chamber
forming a third organic compound layer.
7. A deposition apparatus according to claim 6, wherein: said first
organic compound layer emits a red light, said second organic
compound layer emits a green light, and said third organic compound
layer emits a blue light.
8. A deposition apparatus according to claim 5, wherein each said
evaporation source has an organic compound selected from the group
consisting of a hole injectability, hole transportability,
luminescent ability, blocking ability, electron transportability,
or electron injectability.
9. A deposition apparatus comprising: a load chamber; an alignment
chamber having a function of performing an alignment of a position
between a metal mask and a substrate; a deposition chamber; and a
plurality of evaporation sources in said deposition chamber;
wherein the load chamber, the alignment chamber, and the deposition
chamber are connected in series; wherein each of the plurality of
evaporation sources comprises at least one organic compound having
a different function; and wherein the organic compounds having the
different functions are continuously deposited by a vacuum
evaporation from said plurality of evaporation sources.
10. A deposition apparatus according to claim 9, wherein the
deposition apparatus comprises: a first deposition chamber forming
a first organic compound layer, a second deposition chamber forming
a second organic compound layer, and a third deposition chamber
forming a third organic compound layer.
11. A deposition apparatus according to claim 10, wherein: said
first organic compound layer emits a red light, said second organic
compound layer emits a green light, and said third organic compound
layer emits a blue light.
12. A deposition apparatus according to claim 9, wherein each said
evaporation source has an organic compound selected from the group
consisting of a hole injectability, hole transportability,
luminescent ability, blocking ability, electron transportability,
or electron injectability.
13. A deposition apparatus comprising: a load chamber; an alignment
chamber having a function of performing an alignment of a position
between a metal mask and a substrate; a deposition chamber; and a
plurality of evaporation sources in said deposition chamber;
wherein the load chamber, the alignment chamber, and the deposition
chamber are connected in series; wherein each of the plurality of
evaporating sources comprises at least one organic compound having
a different function, and wherein at least two of the organic
compounds having the different functions are simultaneously
deposited by a vacuum evaporation from said plurality of
evaporation sources.
14. A deposition apparatus according to claim 13, wherein the
deposition apparatus comprises: a first deposition chamber forming
a first organic compound layer, a second deposition chamber forming
a second organic compound layer, and a third deposition chamber
forming a third organic compound layer.
15. A deposition apparatus according to claim 14, wherein: said
first organic compound layer emits a red light, said second organic
compound layer emits a green light, and said third organic compound
layer emits a blue light.
16. A deposition apparatus according to claim 13, wherein each said
evaporation source has an organic compound selected from the group
consisting of a hole injectability, hole transportability,
luminescent ability, blocking ability, electron transportability,
or electron injectability.
17. A deposition apparatus comprising: a load chamber; a transport
chamber; an alignment chamber having a function of performing an
alignment of a position between a metal mask and a substrate; a
deposition chamber; and a plurality of evaporation sources in said
deposition chamber; wherein said transfer chamber is connected with
said load chamber, said alignment chamber, and said deposition
chamber, respectively; wherein each of the plurality of evaporation
sources comprises at least one organic compound having a different
function; and wherein the organic compounds having the different
functions are continuously deposited by a vacuum evaporation from
said plurality of evaporation sources.
18. A deposition apparatus according to claim 17, wherein the
deposition apparatus comprises: a first deposition chamber forming
a first organic compound layer, a second deposition chamber forming
a second organic compound layer, and a third deposition chamber
forming a third organic compound layer.
19. A deposition apparatus according to claim 18, wherein: said
first organic compound layer emits a red light, said second organic
compound layer emits a green light, and said third organic compound
layer emits a blue light.
20. A deposition apparatus according to claim 17, wherein each said
evaporation source has an organic compound selected from the group
consisting of a hole injectability, hole transportability,
luminescent ability, blocking ability, electron transportability,
or electron injectability.
21. A deposition apparatus comprising: a load chamber; a transport
chamber; an alignment chamber having a function of performing an
alignment of a position between a metal mask and a substrate; a
deposition chamber; and a plurality of evaporation sources in said
deposition chamber; wherein said transfer chamber is connected with
said load chamber, said alignment chamber, and said deposition
chamber, respectively; wherein each of the plurality of evaporation
sources comprises at least one organic compound having a different
function, and wherein at least two of the organic compounds having
the different functions are continuously deposited by a vacuum
evaporation from said plurality of evaporation sources.
22. A deposition apparatus according to claim 21, wherein the
deposition apparatus comprises: a first deposition chamber forming
a first organic compound layer, a second deposition chamber forming
a second organic compound layer, and a third deposition chamber
forming a third organic compound layer.
23. A deposition apparatus according to claim 22, wherein: said
first organic compound layer emits a red light, said second organic
compound layer emits a green light, and said third organic compound
layer emits a blue light.
24. A deposition apparatus according to claim 21, wherein each said
evaporation source has an organic compound selected from the group
consisting of a hole injectability, hole transportability,
luminescent ability, blocking ability, electron transportability,
or electron injectability.
25. A method comprising: forming a first function region comprising
a first organic compound from a first evaporation source by
performing vacuum evaporation in a deposition chamber; forming a
first mixed region comprising said first organic compound and a
second organic compound in said deposition chamber by performing
vacuum evaporation simultaneously from said first evaporation
source and from a second evaporation source; forming a second
function region comprising said second organic compound in said
deposition chamber by performing vacuum evaporation from said
second evaporation source but not from said first evaporation
source; forming a second mixed region comprising said second
organic compound and a third organic compound in said deposition
chamber by performing vacuum evaporation simultaneously from said
second evaporation source and from a third evaporation source but
not from said first evaporation source; and forming a third
function region comprising said third organic compound in said
deposition chamber by performing vacuum evaporation from said third
evaporation source but not from said first evaporation source and
not from said second evaporation source.
26. A deposition method according to claim 25, wherein: said first
function region is formed on an anode, said first organic compound
is an organic compound with hole transportability, said second
organic compound is an organic compound which emits light, and said
third organic compound is an organic compound with an electron
transportability.
27. A deposition method according to claim 25, wherein said organic
compound with a hole transportability comprises aromatic diamine
compound.
28. A deposition method according to claim 25, wherein: said
organic compound with an electron transportability comprises a
metal selected from the group consisting of complex containing
quinoline skeleton, metal complex containing benzoquinoline
skeleton, oxadiazole derivative, triazole derivative or
phenanthroline derivative.
29. A deposition method according to claim 25, wherein: said
organic compound which emits light is selected from the group
consisting of a metal complex containing quinoline skeleton, metal
complex containing benzooxazole skeleton, and metal complex
containing benzothiazole skeleton.
30. A method comprising: forming a first function region comprising
a first organic compound from a first evaporation source by
performing vacuum evaporation in a deposition chamber; forming a
first mixed region comprising said first organic compound and a
second organic compound in said deposition chamber by performing
vacuum evaporation simultaneously from said first evaporation
source and from a second evaporation source; forming a second
function region comprising said second organic compound in said
deposition chamber by performing vacuum evaporation from said
second evaporation source but not from said first evaporation
source; forming a second mixed region comprising said second
organic compound and a third organic compound in said deposition
chamber by performing vacuum evaporation simultaneously from said
second evaporation source and a third evaporation source but not
from said first evaporation source; and after forming said second
mixed region, forming a second function region comprising said
second organic compound in said deposition chamber by performing
vacuum evaporation from said second evaporation source but not from
said first evaporation source and not from said third evaporation
source.
31. A deposition method according to claim 30, wherein: said first
function region is formed on an anode, said first organic compound
is an organic compound with hole transportability, said second
organic compound is an organic compound with an electron
transportability, and said third organic compound is an organic
compound which emits light.
32. A deposition method according to claim 30, wherein said organic
compound with a hole transportability comprises aromatic diamine
compound.
33. A deposition method according to claim 30, wherein: said
organic compound with an electron transportability comprises a
metal selected from the group consisting of complex containing
quinoline skeleton, metal complex containing benzoquinoline
skeleton, oxadiazole derivative, triazole derivative or
phenanthroline derivative.
34. A deposition method according to claim 30, wherein: said
organic compound which emits light is selected from the group
consisting of a metal complex containing quinoline skeleton, metal
complex containing benzooxazole skeleton, and metal complex
containing benzothiazole skeleton.
35. A method comprising: forming a first function region comprising
a first organic compound from a first evaporation source by
performing vacuum evaporation in a first deposition chamber;
forming a first mixed region comprising said first organic compound
and a second organic compound in said first deposition chamber by
performing vacuum evaporation simultaneously from said first
evaporation source and from a second evaporation source; and
forming a second function region comprising said second organic
compound in said first deposition chamber by performing vacuum
evaporation from said second evaporation source but not from said
first evaporation source; forming a third function region
comprising a third organic compound by performing vacuum
evaporation from a third evaporation source in a second deposition
chamber; forming a second mixed region comprising said third
organic compound and a fourth organic compound in said second
deposition chamber by performing vacuum evaporation simultaneously
from said third evaporation source and from a fourth evaporation
source; and forming a fourth function region comprising said fourth
organic compound in said second deposition chamber by performing
vacuum evaporation from said fourth evaporation source but not from
said third evaporation source; forming a fifth function region
comprising a fifth organic compound from a fifth evaporation source
by performing vacuum evaporation in a third deposition chamber;
forming a third mixed region comprising said fifth organic compound
and a sixth organic compound in said third deposition chamber by
performing vacuum evaporation simultaneously from said fifth
evaporation source and from said sixth evaporation source; and
forming a sixth function region comprising said sixth organic
compound in said third deposition chamber by performing vacuum
evaporation from said sixth evaporation source but not from said
fifth evaporation source.
36. A deposition method according to claim 35, wherein: one of said
first function region and said second function region, one of said
third function region and said fourth function region, and one of
said fifth function region and said sixth function region comprises
organic compound materials which emits light, and the other one of
said first function region and said second function region, the
other one of said third function region and said fourth function
region, and the other one of said fifth function region and said
sixth function region comprises organic compounds selected from the
group consisting of a hole injectability, a hole transportability,
a blocking ability, an electron transportability, and an electron
injectability.
37. A deposition method according to claim 36, wherein said organic
compound materials which emits light have a light emission color
different from the other of said organic compound materials,
respectively.
38. A deposition method according to claim 35. wherein said organic
compound with a hole transportability comprises aromatic diamine
compound.
39. A deposition method according to claim 35, wherein: said
organic compound with an electron transportability comprises a
metal selected from the group consisting of complex containing
quinoline skeleton, metal complex containing benzoquinoline
skeleton, oxadiazole derivative, triazole derivative or
phenanthroline derivative.
40. A deposition method according to claim 35, wherein: said
organic compound which emits light is selected from the group
consisting of a metal complex containing quinoline skeleton, metal
complex containing benzooxazole skeleton, and metal complex
containing benzothiazole skeleton.
41. A method of manufacturing an organic compound element
comprising steps of: during a first period, forming a first organic
layer over a substrate by performing vacuum evaporation from a
first evaporation source in a deposition chamber; during a second
period after said first period, forming a mixed region over the
first organic layer by performing vacuum evaporation from the first
evaporation source and from a second evaporation source in the
deposition chamber; during a third period after said second period,
forming a second organic layer over the mixed region by performing
vacuum evaporation from the second evaporation source but not from
the first evaporation source in the deposition chamber.
42. A method of manufacturing an organic compound element in a
deposition apparatus, a load chamber, an alignment chamber, and a
deposition chamber connected in series in the deposition apparatus,
wherein a position between a metal mask and a substrate is
controlled in the alignment chamber; the method comprising steps
of: during a first period, forming a first organic layer over said
substrate by performing vacuum evaporation from a first evaporation
source in the deposition chamber; during a second period after said
first period, forming a mixed region over the first organic layer
by performing vacuum evaporation from the first evaporation source
and from a second evaporation source in the deposition chamber;
during a third period after said second period, forming a second
organic layer over the mixed region by performing vacuum
evaporation from the second evaporation source but not from the
first evaporation source in the deposition chamber.
43. A method of manufacturing an organic compound element in a
deposition apparatus, each of a load chamber, a transfer chamber,
and an alignment chamber connected with a deposition chamber in the
deposition apparatus, respectively; wherein a position between a
metal mask and a substrate is controlled in the alignment chamber;
the method comprising steps of: during a first period, forming a
first organic layer over the substrate by performing vacuum
evaporation from a first evaporation source in the deposition
chamber; during a second period after said first period, forming a
mixed region over the first organic layer by performing vacuum
evaporation from the first evaporation source and from a second
evaporation source in the deposition chamber; during a third period
after said second period, forming a second organic layer over the
mixed region by performing vacuum evaporation from the second
evaporation source but not from the first evaporation source in the
deposition chamber.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the invention
[0002] The invention relates to a luminescent device using an
organic luminescent element having an anode, a cathode, and a film
(referred below to as "organic compound layer"), which includes an
organic compound adapted to effect luminescence upon application of
an electric field. Specifically, the present invention relates to a
manufacturing of a luminescent element which requires a lower drive
voltage and has a longer life than luminescent devices of the
related art. Further, the luminescent device described in the
specification of the present application indicates an image display
device or a luminescent device, which use an organic luminescent
element as luminescent element. Also, the luminescent device
includes all of modules, in which a connector, for example, an
anisotropic electroconductive film (FPC:Flexible printed circuit)
or a TAB (Tape Automated Bonding) tape or a TCP (Tape Carrier
Package) is mounted to an organic luminescent element, modules, in
which a printed-circuit board is provided on a TAB tape or a tip
end of a TCP, or modules, in which an IC (integrated circuit) is
directly mounted on an organic luminescent element in the COG (Chip
On Glass) system.
[0003] 2. Description of the Related Art
[0004] An organic luminescent element is one adapted to effect
luminescence upon application of an electric field. A mechanism for
luminescence has been said to reside in that an organic compound
layer is interposed between electrodes, upon application of voltage
thereto electrons filled from a cathode and holes filled from an
anode recombine together at a center of luminescence in the organic
compound layer to form molecule excitons, and the molecule excitons
discharge energy to produce luminescence when returned to the base
state.
[0005] In addition, kinds of molecule excitons formed by the
organic compound can include a singlet excited state and a triplet
excited state, while the specification of the present invention
contains the case where either of the excited states contributes to
luminescence.
[0006] In such organic luminescent element, an organic compound
layer is normally formed in a thin film below 1 .mu.m. Also, since
the organic luminescent element is a self-luminescent type one, in
which the organic compound layer itself emits light, a backlight
used in a conventional liquid crystal display is not necessary.
Accordingly, the organic luminescent element can be very
advantageously formed to be thin and lightweight.
[0007] Also, with, for example, an organic compound layer of about
100 to 200 nm in thickness, a time period having elapsed from
filling of a carrier to recombination thereof is in the order of
several tens of nanosecond taking account of the extent of movement
of the carrier in the organic compound layer, and luminescence is
achieved in the order of less than one micro second even when the
procedure from the recombination of the carrier to luminescence is
included. Accordingly, one of the features is that the speed of
response is very large.
[0008] Further, since the organic luminescent element is a
carrier-filling type luminescent element, it can be driven by DC
voltage, and is hard to generate noise. With respect to drive
voltage, an adequate luminance of 100 cd/m.sup.2 is achieved at 5.5
V by first making the thickness of an organic compound layer a
uniform, super-thin film of around 100 nm, selecting an electrode
material, which reduces a carrier filling barrier relative to the
organic compound layer, and further introducing a single hetero
structure (double structure) (Literature 1: C. W. Tang and S. A.
VanSlyke, "Organic electroluminescent diodes", Applied Physics
Letters, vol. 51, No. 12, 913-915 (1987)).
[0009] Owing to such performances as thin and lightweight,
high-speed responsibility, DC low voltage drive, and the like,
organic luminescent elements have been given attention as
next-generation flat panel display elements. Also, since organic
luminescent elements are of self-luminescent type and large in
angle of visibility, they are comparatively favorable in visibility
and believed to be effective as elements used for displays in
portable equipments.
[0010] Hereupon, in the constitution of an organic luminescent
element described in Literature 1, a carrier filling barrier is
made small by using as a cathode a relatively 30 stable Mg:Ag alloy
of low work function to enhance an electron injecting quality. This
makes it possible to fill a large amount of carrier into the
organic compound layer.
[0011] Further, the recombination efficiency of the carrier is
improved by leaps and bounds by application of a single hetero
structure, in which a hole transporting layer composed of a diamine
compound and an electron transporting luminescent layer composed of
tris (8-quinolinolato) aluminium (hereinafter written as
"Alq.sub.3") are laminated as an organic compound layer, which is
explained below.
[0012] In the case of, for example, an organic luminescent element
having only a single Alq.sub.3 layer, a major part of electrons
filled from a cathode reaches an anode without recombining with
holes, making the luminescent efficiency very low, since Alq.sub.3
is of electron transporting quality. That is, in order to have the
single-layered organic luminescent element efficiently emitting
light (or driving at low voltage), it is necessary to use a
material (referred below to as "bipolar material") capable of
carrying both electrons and holes in well-balanced manner, and
Alq.sub.3 does not meet such requirement.
[0013] However, application of the single hetero structure
described in Literature 1 causes electrons filled from a cathode to
be blocked by an interface between the hole transporting layer and
the electron transporting luminescent layer to be enclosed in the
electron transporting luminescent layer. Accordingly, the carrier
is efficiently recombined in the electron transporting luminescent
layer to provide for efficient luminescence.
[0014] When the concept of such carrier blocking function is
developed, it becomes possible to control a carrier recombining
region. As an example, there is a report, according to which
success is achieved in enclosing holes in a hole transporting layer
and making the hole transporting layer luminescent by inserting a
layer (hole blocking layer), which is capable of blocking holes,
between the hole transporting layer and an electron transporting
layer (Literature 2: Yasunori KIJIMA, Nobutoshi ASAI and
Shin-ichiro TAMURA, "A Blue Organic Luminescent Diode", Japanese
Journal of Applied Physics, Vol. 38, 5274-5277 (1999)).
[0015] Also, it can be said that the organic luminescent element
described in Literature 1 is based on, so to speak, that thought of
functional separation, according to which carrying of holes is
performed by the hole transporting layer and carrying and
luminescence of electrons are performed by the electron
transporting luminescent layer. Such concept of functional
separation has further grown to a concept of double heterostructure
(three-layered structure), according to which a luminescent layer
is inserted between the hole transporting layer and the electron
transporting layer (Literature 3: Chihaya ADACHI, Shizuo TOKITO,
Tetsuo TSUTSUI and Shogo SAITO, "Electroluminescence in Organic
Films with Three-Layered Structure", Japanese Journal of Applied
Physics, Vol. 27, No. 2, L269-L271 (1988)).
[0016] Such functional separation has an advantage in that the
functional separation makes it unnecessary for a kind of organic
material to have a variety of functions (luminescence, carrier
carrying quality, filling quality of carrier from electrode, and so
on) at a time, which provides a wide freedom in molecular design or
the like (for example, it is unnecessary to unreasonably search for
bipolar materials). That is, a high luminous efficiency can be
easily attained by combining materials having a good luminous
quality and a carrier carrying quality, respectively.
[0017] Owing to these advantages, the concept of the laminated
structure (carrier blocking function or functional separation)
itself described in Literature 1 has been widely utilized till
now.
[0018] It is also noted that in the fabrication of these
luminescent elements, in particular in mass-production processes, a
deposition apparatus of the in-line type (multi-chamber scheme) is
typically employed in order to prevent contamination of respective
materials upon lamination of a hole transport material and a
luminescent material, and an electron transport material or the
like by vacuum evaporation. Additionally an upper plan view of such
deposition apparatus is shown in FIG. 13. In the deposition
apparatus shown in FIG. 13, it is possible to perform a vacuum
evaporation of a cathode and a three-layer lamination structure
(double-heterostructure) of a hole transport layer and a
luminescent layer, and an electron transport layer on a substrate
having an anode (such as ITO or else), and to perform a sealing
processing thereof.
[0019] Firstly, transfer a substrate with the anode into a carry-in
chamber. The substrate is transferred through a first transfer
chamber toward an ultraviolet ray irradiation chamber, and is then
subjected to cleaning treatment on the surface of such anode, by
irradiation of ultraviolet rays in a vacuum environment. Note here
that in case the anode is made of oxides such as ITO, the anode is
oxidized here in a pretreatment chamber.
[0020] Next, a hole transport layer is formed in a vapor
evaporation chamber 1301 while forming luminescent layers (in FIG.
13, three colors of red, green and blue) in vacuum evaporation
chambers 1302 to 1304, and forming an electron transport layer in a
vacuum evaporation chamber 1305, and then forming a cathode in a
vacuum evaporation chamber 1316. Lastly, sealing processing is
carried out in a sealing chamber, thereby obtaining a luminescent
element from a carry-out chamber.
[0021] One feature unique to the deposition apparatus of the inline
type is that vacuum evaporation of respective layers are being
performed in different vacuum evaporation chambers 1301 to 1305
respectively. Accordingly, each of the vacuum evaporation chambers
1301 to 1305 may ordinarily be provided with a single evaporation
source (note however that in the vacuum evaporation chambers 1302
to 1304, two evaporation sources will possibly be required from
time to time for formation of a co-vacuum evaporation layer in the
case of fabrication of a luminescent layer by doping pigment
thereinto). To be brief, a specific apparatus arrangement is
employed, in which materials of respective layers are hardly mixed
into each other.
[0022] However, being a junction between substances of different
kinds (in particular, a junction between insulating materials), the
laminated structure described above will necessarily produce an
energy barrier at an interface the substances. Since the presence
of an energy barrier inhibits movements of a carrier at the
interface, the two following problems are caused.
[0023] One of the problems is that it results in a barrier leading
to further reduction of drive voltage. Actually, it has been
reported with respect to existing organic luminescent elements that
an element of a single-layered structure making use of a conjugate
polymer is excellent in terms of drive voltage and holds top data
(comparison in luminescence from the singlet excited state) in
power efficiency (unit:"1m/W") (Literature 4: Tetsuo Tsutsui
"bulletin of organic molecular/bioelectronics" subcommittee of
Society of Applied Physics, Vol. 11, No. 1, P. 8 (2000)).
[0024] In addition, the conjugate polymer described in Literature 4
is a bipolar material, and can attain a level equivalent to that of
the laminated structure with respect to the recombination
efficiency of a carrier. Accordingly, it demonstrates that a single
layer structure having less interfaces is actually low in drive
voltage provided that a method making use of a bipolar material can
make an equivalent recombination efficiency of a carrier without
the use of any laminated structure.
[0025] For example, there is a method, in which a material for
mitigating an energy barrier is inserted at an interface between an
electrode and an organic compound layer to enhance a carrier
filling quality to reduce drive voltage (Literature 5: Takeo
Wakimoto, Yoshinori Fukuda. Kenichi Nagayama, Akira Yokoi, Hitoshi
Nakada, and Masami Tsuchida, "Organic EL Cells Using Alkaline Metal
Compounds as Electron Injection Materials", IEE TRANSACTIONS ON
ELECTRON DEVICES, VOL. 44, NO. 8, 1245-1248 (1977)). In Literature
5, the use of Li.sub.2O as an electron injecting layer has been
successful in reduction of drive voltage.
[0026] However, the carrier transfer between organic materials
(e.g., between the hole transport layer and luminescent layer; the
interface will hereinafter be called "organic interface") remains
as an unsettled issue and is considered to be an important point in
catching up with the low drive voltage provided by the
single-layered structure.
[0027] Further, the other problem caused by an energy barrier is
believed to be an influence on the service life of organic
luminescent elements. That is, movements of a carrier are impeded,
and brilliance is lowered due to build-up of charges.
[0028] While any definite theory has not been established with
respect to such mechanism of deterioration, there is a report that
lowering of brilliance can be suppressed by inserting a hole
injecting layer between an anode and a hole transporting layer and
employing not DC driving but AC driving of rectangular wave
(Literature 6: S. A. VanSlyke, C. H. Chen, and C. W. Tang, "Organic
electroluminescent devices with improved stability", Applied
Physics Letters, Vol. 69, No. 15, 2160-2162 (1996)). This can be
said to present an experimental evidence that lowering of
brilliance can be suppressed by eliminating accumulation of charges
due to insertion of a hole injecting layer and AC driving.
[0029] It can be said from the above that on one hand the laminated
structure has an advantage in enabling easily enhancing the
recombination efficiency of a carrier and enlarging a range of
material selection in terms of functional separation and on the
other hand formation of many organic interfaces impedes movements
of a carrier and has an influence on lowering of drive voltage and
brilliance.
[0030] Additionally in the prior art deposition apparatus,
lamination of the hole transport material and luminescent layer
material, electron transport material or else is done in separate
chambers provided with its own evaporation source in order to
prevent contamination of respective materials. However, such
apparatus is encountered with problems that organic interfaces are
clearly separated and when a substrate is driven to move between
chambers, impurities such as water and oxygen can be mixed into the
organic interface, in the case of forming the above-noted
multilayer structure,.
SUMMARY OF THE INVENTION
[0031] Hence, the present invention provides deposition apparatuses
based on concepts different from the prior used multilayer
structures for fabricating an element having functions of a variety
of kinds of materials in a similar manner to the function
separation of multilayer structures while at the same time relaxing
energy barriers present in organic compound layers to thereby
enhance the mobility of electrical carriers. Another object of the
invention is to provide deposition method employing these
deposition apparatuses.
[0032] Regarding the energy barrier relaxation in multilayer
structures, it is remarkably seen in the technique for insertion of
a carrier injection layer as found in the Document 5. In other
words, at the interface of a multilayer structure having a large
energy barrier, insertion of a material for relaxing such energy
barrier makes it possible to design the energy barrier into the
form of a stair step-like shape.
[0033] With such an arrangement, it is possible to increase the
injectability of electrical carriers from an electrode and to
reduce a drive voltage to a certain degree. However, a problem
faced with this approach is that an increase in requisite number of
layers would result in an increase in organic interface number. As
suggested from Document 4, this is considered to be a cause for the
fact that single-layer structures are superior to multilayer
structures in holding of the top-class data as to the drive voltage
and power efficiency.
[0034] Adversely, overcoming this point makes it possible to catch
up the drive voltage/power efficiency of single-layer structure
while at the same time maintaining the merits of multilayer
structures (enabling combination of a variety of materials while
avoiding the need for any complicated molecular design).
[0035] Then in the present invention, in the case of forming an
organic compound layer 103 consisting a plurality of function
regions between an anode 101 and a cathode 102 in a luminescent
element as shown in FIGS. 1A and 1B. not the prior art multilayer
structure with the presence of distinct interfaces (FIG. 1A) but a
structure (FIG. 1B) having a mixed region 106 comprising both a
material constituting a first function region 104 and a material
constituting a second function region 105 between the first
function region 104 and the second function region 105 is
formed.
[0036] It is considered that applying the structure shown in FIG.
1B causes any energy barrier existing between function regions to
decrease when compared to the prior art structure shown in FIG. 1A,
resulting in an improvement in carrier injectability. Practically,
while an energy band diagram in the structure of FIG. 1A is as
shown in FIG. 1C, in the case of forming a structure with a mixed
region between function regions as shown in FIG. 1B, its energy
band diagram becomes as shown in FIG. 1D. To be brief, the energy
barrier between function regions is relaxed by formation of such
mixed region therebetween. Thus, it becomes possible to prevent
drive voltage drop-down and luminance reduction.
[0037] From the foregoing, with deposition apparatus of the present
invention, in the manufacture of a luminescent element which at
least includes a region (first function region) which a first
organic compound can express function and a region (second function
region) which a second organic compound different from the
substance consisting the first function region can express function
and also of a luminescent device having the luminescent element, a
feature unique thereto is that a mixed region comprised of the
organic compound constituting the first function region and organic
compound constituting the second function region is fabricated
between the first function region and the second function
region.
[0038] It should be noted that the first organic compound and
second organic compound are different in nature from each other
while each having its nature as selected from the group consisting
of hole injectability for receipt of holes from the anode, hole
transportability with hole mobility greater than electron mobility,
electron transportability with electron mobility greater than hole
mobility, electron injectability for receipt of electrons from the
cathode, blocking ability for enabling preclusion of movement of
either holes or electrons, and luminescent ability exhibiting
luminescence.
[0039] Also note that the organic compound with high hole
injectability is preferably made of phthalocyanine-based compound;
the organic compound with high hole transportability may be
aromatic diamine compound, and, the organic compound with high
electron transportability may be a metal complex that contains
therein quinoline skeleton, metal complex containing benzoquinoline
skeleton or oxadiazole derivative or triazole derivative or
phenanthroline derivative. Furthermore, the organic compound
exhibiting luminescence may preferably be a metal complex
containing therein quinoline skeleton with stabilized light
emission, metal complex containing benzooxazole skeleton, or metal
complex containing benzothiazole skeleton.
[0040] Some combinations of the above-stated first function region
and the second function region are shown in Table 1 presented
below. Combinations A to E may be employable solely (e.g. only "A")
or alternatively some of them are introduced together in a
composite fashion (e.g. both "A" and "B").
1TABLE 1 Combination 1st Function Region 2nd Function Region A Hole
Injectability Hole Transportability B Electron Injectability
Electron Transportability C Hole Transportability Luminescent
ability D Electron Transportability Luminescent ability E Electron
Transportability Blocking Ability
[0041] Additionally in the case of introduction with composite use
of the combinations C and D (that is, when introducing a mixed
region at the both interfaces of a function region with luminescent
ability), by preventing diffusion of molecular excitons formed in
the luminescent region, it is possible to further increase the
luminescent efficiency. Thus it will be preferable that the
excitation energy of such luminescent region is lower than the
excitation energy of the hole region and the excitation energy of
electron transport region. In this case, since luminescent material
poor in carrier transportability is also utilizable as the
luminescent region, there is an advantage that the range of
selecting material expands accordingly. Note here that the term
"excitation energy" used in this specification is to be understood
to mean an energy difference between the highest occupied molecular
orbital (HOMO) and the lowest unoccupied molecular orbital
(LUMO).
[0042] More preferably, it is designed so that the luminescent
region is comprised of both host material and luminescent material
(dopant) low in excitation energy than the host material and
designed such that the excitation energy of such dopant is lower
than the excitation energy of hole transport region and the
excitation energy of electron transport layer. With such an
arrangement, it is possible to permit the dopant to produce light
efficiently while at the same time preventing diffusion of the
dopant's molecular excitons. In addition, if the dopant is made of
certain material of the carrier trap type then it is also possible
to increase the recombination efficiency of carriers.
[0043] Hereupon, in view of the luminescent efficiency, organic
luminescent elements capable of converting energy (referred below
to as "triplet excited energy"), which is discharged when returned
to a base state from a triplet excited state, into luminance, have
been successively presented, and notice has been taken of their
luminous efficiency (Literature 7: D. F. O'Brien, M. A. Baldo, M.
E. Thompson and S. R. Forrest, "Improved energy transfer in
electrophosphorescent devices", Applied Physics Letters, Vol. 74,
No. 3, 442-444 (1999)), (Literature 8: Tetsuo TSUTSUI, Moon-Jae
YANG, Masayuki YAHIRO, Kenji NAKAMURA, Teruichi WATANABE, Taishi
TSUJI, Yoshinori FUKUDA, Takeo WAKIMOTO and Satoshi MIYAGUCHI,
"High Quantum Efficiency in Organic Luminescent devices with
Iridium-Complex as a Triplet Emissive Center", Japanese Journal of
Applied Physics, Vol. 38, L1502-L1504 (1999)).
[0044] A metal complex, of which central metal is platinum, is used
in Literature 7, and a metal complex, of which central metal is
iridium, is used in Literature 8. These organic luminescent
elements capable of converting triplet excited energy into
luminance (referred below to as "triplet luminescent diode") can
attain higher intensity luminance and higher luminous efficiency
than in the related art.
[0045] However, Literature 8 has presented an example, in which
half-life of luminance is about 170 hours in the case where the
initial luminance is set to 500 cd/m.sup.2, thus causing a problem
in service life of an element. Hereupon, application of the
invention to triplet light emitting diodes can provide a highly
functional luminescent element, which is long in service life in
addition to high intensity luminance and high luminous efficiency
based on luminance from a triplet excited state.
[0046] Consequently the case of adding a material capable of
converting the triplet excitation energy to light emission into the
mixed region as a dopant will also be included in the present
invention. Additionally in the formation of such mixed region, it
is permissible that the mixed region has a concentration
gradient.
[0047] With the deposition apparatus of the present invention, the
feature lies in that a plurality of function regions are deposited
within the same deposition chamber having a plurality of
evaporation sources to thereby form a luminescent element having
the mixed region stated supra.
[0048] An explanation will now be given of a deposition chamber 210
as used in the deposition apparatus of this invention with
reference to FIG. 2A. As shown in FIG. 2A. a metal mask 202 being
fixed to a holder 201 is furnished beneath a substrate 200, with an
evaporation source 203a to 203c being provided further beneath it.
Evaporation sources 203 (203a to 203c) comprises organic compounds
204 (204a to 204c) for fabrication of organic compound layer,
material chambers 205 (205a to 205c) for preparing the organic
compounds therein, and shutters 206 (206a to 206c). Note here that
in the deposition apparatus of this invention, it is recommendable
that either the evaporation source or a substrate to be subjected
to vacuum evaporation be movably (rotatably) arranged to ensure
that film is fabricated uniformly.
[0049] Meanwhile, the material chambers 205 (205a to 205c) are made
of conductive metal material and have a structure shown in FIG. 17.
Note that the organic compounds 204 (204a to 204c) are vaporized
and then deposited onto a surface of the substrate 200 upon heat up
of the internal organic compounds 204 (204a to 204c) due to
resistance occurring when a voltage is applied to the material
chambers 205 (205a to 205c). Also note that the term "surface of
the substrate 200" is to be understood to involve the substrate and
more than one thin-film as formed over this substrate, here, an
anode is formed on the substrate.
[0050] In addition the shutters 206 (206a to 206c) control vacuum
evaporation of the vaporized organic compounds 204 (204a to 204c).
In brief, when the shutters are opened, it is possible to deposit
the vaporized organic compounds 204 (204a to 204c) due to heat
application by vacuum evaporation.
[0051] Additionally it will be desirable that the organic compounds
204 (204a to 204c) be pre-vaporizable by heat application prior to
the vacuum evaporation process for enabling effectuation of any
vacuum evaporation immediately after the shutters 2()6 (206a to
206c) are opened during vacuum evaporation, thus shortening a time
period required for deposition.
[0052] In addition, in the deposition apparatus embodying the
invention, an organic compound layer having a plurality of function
regions is formed within a single deposition chamber, evaporation
sources 203a to 203c are provided. Organic compounds vaporized at
respective evaporation sources 203a to 203c behave to upwardly and
then pass through openings (not shown) that are defined in the
metal mask 202 to be deposited on the substrate 200.
[0053] Initially a first organic compound 204a furnished in the
first material chamber 205a is subject to vacuum evaporation. Note
here that the first organic compound 204a is vaporized in advance
by resistive heat up and thus dispersed in the direction of
substrate 200 upon opening of the shutter 206a during vacuum
evaporation. Whereby, it is possible to form a first function
region 210 shown in FIG. 2B.
[0054] And, while letting the first organic compound 204a kept
deposited, open another shutter 206b for execution of vacuum
evaporation of a second organic compound 204b furnished in the
second material chamber 205b. Note that the second organic compound
also is pre-vaporized by resistive heat up and thus dispersed in
the direction of substrate 200 upon opening of the shutter 206b
during vacuum evaporation. Here, it is possible to form a first
mixed region 211 which consists essentially of the first organic
compound 204a and the second organic compound 204b.
[0055] And, after a while, close only the shutter 206a for vacuum
evaporation of the second organic compound 204b. Thus it is
possible to form a second function region 212.
[0056] It should be noted that although one specific method for
forming the mixed region through simultaneous vacuum evaporation of
two kinds of organic compounds is shown here, it is also possible
to form the mixed region between the first function region and
second function region by depositing the first organic compound
and, thereafter. depositing the second organic compound in the
vacuum evaporation environment of the first organic compound.
[0057] Next, while letting the second organic compound 204b kept
deposited, open a shutter 206c for execution of vacuum evaporation
of a third organic compound 204c as has been furnished in the third
material chamber 205c. Note that the third organic compound 204c is
also pre-vaporized by resistive heat up and thus dispersed in the
direction of substrate 200 upon opening of the shutter 206c during
vacuum evaporation. Here, it is possible to form a second mixed
region 213 which consists essentially of the second organic
compound 204b and the third organic compound 204c.
[0058] And, after a while close only the shutter 206b for vacuum
evaporation of the third organic compound 204c. Thus it is possible
to form a third function region 214.
[0059] Lastly, a cathode is formed, thereby completing a
luminescent element as fabricated by the deposition apparatus of
the present invention. Further, regarding other organic compound
layers, as shown in FIG. 2C, after forming a first function region
220 using the first organic compound 204a, form a first mixed
region 221 consisting essentially of the first organic compound
204a and the second organic compound 204b, and further form a
second function region 222 by using the second organic compound
204b. Then, simultaneously perform vacuum evaporation of third
organic compound 204c while letting shutter 206c open temporarily
during formation of the second function region 222, thereby forming
a second mixed region 223.
[0060] After a while, close the shutter 206c to thereby again form
the second function region 222. Then form a cathode, thus forming a
luminescent element.
[0061] It must be noted that in view of the fact that with the
deposition apparatus of this invention the deposition is performed
by use of the plurality of material chambers within the same
deposition chamber, a material chamber with the organic material
used for deposition may be designed to move at an optimal location
beneath the substrate during deposition process in order to improve
the deposition property or, alternatively, the substrate is
modified to have a function of moving at an optimal position
overlying the material chamber for the same purpose.
[0062] Furthermore, the deposition chamber of this invention is
provided with an attachment-preventing shield 207 for preventing
attachment of organic compounds to the inner wall of such
deposition chamber during vacuum evaporation. Providing this
attachment-preventing shield 207 makes it possible to deposit those
organic compound components that have failed to be deposited on the
substrate. Around the attachment-preventing shield 207, a heater
208 is provided in contact therewith, wherein the use of this
heater 208 enables the entirety of such attachment-preventing
shield 207 to be heated. Additionally, heating the
attachment-preventing shield 207 makes it possible to vaporize the
organic compounds attached to the shield 207. This in turn makes it
possible to achieve successful cleaning of the interior of
deposition chamber.
[0063] As the deposition apparatus of the invention capable of
fabricating the above-discussed organic compound layers enables
formation of an organic compound layer having a plurality of
function regions within the same deposition chamber, it is possible
to form a mixed region at the interface between function regions
without letting the function region interface be contaminated by
impurities. From the foregoing, it is apparent that a luminescent
element comprising multiple functions is manufacturable without
showing any distinct multilayer structures (that is, without
associating any distinct organic interfaces).
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] FIGS. 1A through 1D are diagrams for explanation of an
element structure as fabricated by a deposition apparatus of the
present invention;
[0065] FIG. 2A is a diagram for explanation of a deposition chamber
and FIGS. 2B and 2C are diagrams of elements as fabricated by a
deposition chamber shown in FIG. 2A;
[0066] FIGS. 3A and 3B are diagrams explaining about a deposition
apparatus;
[0067] FIGS. 4A through 4E are diagrams for explanation of a metal
mask alignment method;
[0068] FIG. 5 is a diagram explaining on a deposition
apparatus;
[0069] FIGS. 6A and 6B are diagrams explaining on a deposition
chamber;
[0070] FIGS. 7A and 7B are diagrams explaining on a deposition
apparatus;
[0071] FIGS. 8A and 8B are diagrams explaining on a deposition
apparatus;
[0072] FIG. 9 is a diagram explaining on a luminescent device;
[0073] FIGS. 10A and 10B are diagrams explaining on a seal
structure;
[0074] FIG. 11 is a diagram explaining on a luminescent device;
[0075] FIGS. 12A through 12H are diagrams showing examples of
electrical instruments;
[0076] FIG. 13 is a diagram for explanation of one typical prior
art:
[0077] FIG. 14 is a diagram explaining on a deposition apparatus;
and
[0078] FIG. 15 is a diagram explaining on a luminescent device.
[0079] FIGS. 16A through 16C are diagrams explaining on a pixel
portion.
[0080] FIG. 17 is a diagram explaining on material chambers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0081] [Embodiment Mode]
[0082] An arrangement of deposition apparatus of the present
invention will be explained with reference to FIGS. 3A and 3B. FIG.
3A is a diagram showing an upper plan view of the deposition
apparatus, and FIG. 3B shows a cross-sectional view thereof. Note
here that common components will be designated by common reference
numerals. Also there is shown an example which is arranged so that
three kinds of organic compound layers (red, green, blue) are
formed in each deposition chamber of a deposition apparatus of the
inline scheme having three deposition chambers.
[0083] In FIG. 3A, reference numeral "300" denotes a loading
chamber, wherein a substrate prepared in this load chamber is
transferred toward a first alignment chamber 301. Note that in the
first alignment chamber 301, alignment of a metal mask 303 fixed to
a holder 302 in advance is done with the holder 302, thereby a
substrate 304 of pre-vacuum evaporation is formed on the
alignment-finished metal mask 303, wherein one electrode (here,
anode) comprising a luminescent element is formed on the substrate
304. Whereby, the substrate 304 and metal mask 303 are made
integral together to be transferred toward a first deposition
chamber 305.
[0084] An explanation will now be given of a positional
relationship of the holder 302 for fixation of the metal mask 303
and substrate 304 with reference to FIGS. 4A through 4E. Note that
in these drawings, components identical to those of FIGS. 3A and 3B
will be denoted by the same reference numerals.
[0085] A sectional structure is shown in FIG. 4A. The holder 302
shown herein is generally constituted from a mask holder 401, a
shaft 402, a substrate holder 403, control mechanism 404 and
auxiliary pins 405. Additionally the metal mask 303 is fixed in a
way aligned with a projection 406 on the mask holder 401, with the
substrate 304 mounted on the metal mask 303. Additionally the
substrate 304 on the metal mask 303 is fixed by the auxiliary pins
405.
[0086] An upper plan view in a region 407 of FIG. 4A is shown in
FIG. 4B. Additionally the substrate 304 is fixed by the substrate
holder 403 shown in FIG. 4A and FIG. 4B. Further, a sectional view
as taken along line B-B' of FIG. 4B is shown in FIG. 4C. Assuming
that the position of the metal mask 303 shown in FIG. 4C is at the
time of deposition, a position of the metal mask 303 shown in FIG.
4D with the shaft 402 moved in Z-axis direction is during alignment
process.
[0087] At the process step of FIG. 4D, the shaft 402 is movable in
any one of X-axis and Y-axis, and Z-axis directions, further,
movement of gradient (0) of an X-Y plane with respect to the Z-axis
is also possible. Additionally, the control mechanism 404 outputs a
movement information from both a position information obtained from
a charge-coupled device (CCD) camera and a position information
input therein in advance, thereby the position of the mask holder
can be identical with a specified position through the shaft 402
coupled to the control mechanism 404.
[0088] In addition, an enlarged view of the metal mask 303 in a
region 408 is shown in FIG. 4E. The metal mask 303 as used herein
is structured from a mask a409 and a mask b410 formed using
different materials each other. Additionally during vacuum
evaporation, organic compounds that have passed through these
openings 411 will be fabricated on the substrate. Their shapes are
contrived to improve the deposition accuracy upon execution of
vacuum evaporation using the masks, and are used in such a manner
that the substrate 304 and the mask b410 are in contact with each
other.
[0089] When alignment of the metal mask 303 is completed, let the
shaft move in the Z-axis direction causing the metal mask 303 to
again move at the position of FIG. 4C and then let the metal mask
303 and substrate 304 be fixed together by the auxiliary pins 405,
thus making it possible to complete the alignment of the metal mask
303 along with the positioning between the metal mask 303 and the
substrate 304.
[0090] Note that in this embodiment, the openings of the metal mask
303 may be of a rectangular, elliptical, or linear shape, in
addition, these may be designed into a matrix-like layout or delta
layout.
[0091] The first deposition chamber 305 in FIG. 3A is provided with
a plurality of evaporation sources 306. Additionally each the
evaporation sources 306 consists of a material chamber (not shown)
in which organic compounds are prepared and a shutter (not shown)
for controlling through open/close operations dispersion of
vaporized organic compound in the material chamber toward outside
of the material chamber.
[0092] In addition, the plurality of evaporation sources 306
provided in the first deposition chamber 305 are provided with
organic compounds having different functions for constituting an
organic compound layer of a luminescent element. respectively. Note
here that the organic compounds as used herein may refer to organic
compounds having its nature of hole injectability for receipt of
holes from the anode, hole transportability with hole mobility
greater than electron mobility, electron transportability with
electron mobility greater than hole mobility, electron
injectability for receipt of electrons from the cathode, blocking
ability for enabling inhibition of movement of either holes or
electrons, and luminescent ability exhibiting light emission.
[0093] Note here that the organic compound with a high hole
injectability may preferably be phthalocyanine-based compound; the
organic compound with a high hole transportability is preferably
aromatic diamine compound; and, the organic compound with a high
electron transportability is preferably a metal complex containing
benzoquinoline skeleton, oxadiazole derivative, triazole
derivative, or still alternatively phenanthroline derivative.
Further, the organic compound exhibiting luminescent ability is
preferably a metal complex containing quinoline skeleton, metal
complex containing benzooxazole skeleton, or metal complex
containing benzothiazole skeleton which emit a steady light.
[0094] In the first deposition chamber 305, the organic compounds
provided in these evaporation sources are deposited by a vacuum
evaporation in order, using the method discussed in FIG. 2A,
resulting in formation of a first organic compound layer (here,
red) having a plurality of function regions and mixed regions.
[0095] Next, the substrate 304 is transported toward a second
alignment chamber 307. In the second alignment chamber 307, after
once substrate 304 is separated from the metal mask 303, alignment
of the metal mask 303 is done in such a manner that it matches a
position whereat a second organic compound layer is to be
fabricated. And, after completion of the alignment, the substrate
304 and the metal mask 303 are overlapped with each other and fixed
together.
[0096] And, transfer the substrate 304 toward a second deposition
chamber 308. Similarly the second deposition chamber 308 is also
provided with a plurality of evaporation sources. In a similar way
to the first deposition chamber 305. a plurality of organic
compounds are deposited by a vacuum evaporation in order, resulting
in formation of a second organic compound layer (here, green)
having a plurality of function regions and mixed regions.
[0097] Further, transfer the substrate 304 toward a third alignment
chamber 309. In the third alignment chamber 309, after once the
substrate 304 is separated from the metal mask 303, alignment of
the metal mask 303 is done in such a way that it matches a position
whereat a third organic compound layer is to be fabricated. And,
after completion of the alignment, the substrate 304 and metal mask
303 are overlapped with each other and fixed together.
[0098] And, transfer the substrate 304 to a third deposition
chamber 310. Similarly the third deposition chamber 310 is also
provided with a plurality of evaporation sources. In a similar way
to that of the other deposition chambers, a plurality of organic
compounds are deposited by a vacuum evaporation in order, resulting
in formation of a third organic compound layer (here, blue) having
a plurality of function regions and mixed regions.
[0099] Lastly the substrate 304 is transferred to an unload chamber
31 1 and then taken outwardly of the deposition apparatus.
[0100] Performing in this way the alignment of the metal mask 303
in the alignment chamber once at a time whenever a different
organic compound layer is formed, a plurality of organic compound
layers can be formed within the same apparatus. As function regions
consisting of a single organic compound layer is deposited in the
same deposition chamber in this way, it is possible to avoid
impurity contamination between adjacent function regions.
Furthermore in this deposition apparatus, since it is possible to
form a mixed region between different function regions, it becomes
possible manufacture a luminescent element having multiple
functions without indicating any distinct multilayer
structures.
[0101] Additionally although there is shown in this embodiment a
deposition apparatus which operates up to the formation of the
organic compound layers, the deposition apparatus of the present
invention should not be limited only to this structure and may
alternatively be modified to have a structure comprising a
deposition chamber in which the cathode is formed on an organic
compound layer and a processing chamber capable of sealing the
luminescent element. Additionally the deposition order of the
organic compound layers which emit red, green and blue light should
not be limited to the above-stated one.
[0102] Moreover, there may also be provided a means for cleaning
the alignment and deposition chambers as indicated in this
embodiment mode. Also note that in case such means is provided in
the region 312 of FIG. 3, it is possible to provide a cleaning
preliminary chamber 313 shown in FIG. 14.
[0103] In the cleaning preliminary chamber 313, let radicals
generate by decomposition of a reactive gas such as NF.sub.3 or
CF.sub.4 and then introduce them into the second alignment chamber
307 to thereby enable cleaning at the second alignment chamber 307.
Note here that the metal mask can be cleanup by providing used
metal mask in the second alignment chamber 307 in advance. Also
note that introducing the radicals into the second deposition
chamber 308 also makes it possible to clean up the inside of the
second deposition chamber 308. Additionally the second alignment
chamber 307 and second deposition chamber 308 are connected with
the cleaning preliminary chamber 313 through gates (not shown)
respectively, wherein the gates are designed to open upon
introduction of radicals.
[0104] [Embodiment 1]
[0105] An explanation will be given of the case where the
deposition apparatus of the present invention is the inline scheme,
with reference to FIG. 5. In FIG. 5. reference numeral 501 denotes
a load chamber, from which a substrate is transported. Note that
the term substrate as used in this embodiment is to be understood
to mean the one with either an anode or cathode (anode used in this
embodiment) for use as one electrode of a luminescent element being
formed thereon. In addition the load chamber 501 comes with a gas
exhaust system 500a, wherein this exhaust system 500a is
constituted including a first valve 51, a turbo molecular pump 52,
a second valve 53, a third valve 54 and a dry pump 55.
[0106] Additionally in this embodiment, as the material used for
inside of respective processing chambers such as a gate-blocked
load chamber, an alignment chamber, a deposition chamber, a sealing
chamber and an unloading chamber, a material such as aluminum or
stainless steel (SUS) with mirror surfaces through treatment of
electro polishing is used on the internal wall planes thereof due
to its capability to reduce an adsorption of the impurity such as
oxygen and water by making surface area of the inside wall smaller.
In addition, internal members made of material such as ceramics or
else are employed as the inside material which are treated that
pores become extremely less. Note that these materials have surface
smoothness with the center average roughness being less than or
equal to 30 .ANG..
[0107] Although the first valve 51 is a main valve having a gate
valve, a butterfly valve that functions also as a conductance valve
will alternatively be used. The second valve 53 and the third valve
54 are fore valves. First, a pressure of the load chamber 501 is
roughly reduced by the dry pump 55 with the second valve 53 opened,
next, a pressure of the load chamber 501 is reduced to a high
degree of vacuum by the turbo molecular pump 52 with the first
valve 51 and third valve 54 open. Note that the turbo molecular
pump may be replaced with a mechanical booster pump; alternatively,
the turbo molecular pump is usable after increased the vacuum
degree by the mechanical booster pump.
[0108] Next, the one indicated by numeral 502 is an alignment
chamber. Here, alignment of a metal mask and positioning of a
substrate on the metal mask are done for deposition at a deposition
chamber to which it will next be transferred. This will be called
alignment chamber A502. Additionally, the method explained in FIGS.
4A through 4E may be employed in the alignment method here.
Additionally the alignment chamber A502 comprises a gas exhaust
system 500b and is shut and shielded from the load chamber 501 by a
gate, not shown.
[0109] Further, the alignment chamber A502 is provided with a
cleaning preliminary chamber 513a for producing therein radicals by
decomposition of a reactive gas such as NF.sub.3 or CF.sub.4 or
else and then introducing this into the alignment chamber A502, to
thereby enable of cleanup at the alignment chamber A502. Note that
the used metal mask can be cleanup by providing the metal mask in
the alignment chamber A502 in advance.
[0110] Next, numeral 503 denotes a deposition chamber for
fabrication of a first organic compound layer by vacuum evaporation
methods, which will be called deposition chamber A503 hereinafter.
The deposition chamber A503 comprises an exhaust system 500c. In
addition, this is shut and shielded from the alignment chamber A502
by a gate, not shown.
[0111] In a similar way to the alignment chamber A502, the
deposition chamber A503 is provided with a cleaning preliminary
chamber 513b. Note here that the interior of the deposition chamber
A503 can be cleanup by introducing into the deposition chamber A503
radicals produced through decomposition of a reactive gas such as
NF.sub.3 or CF.sub.4 or else.
[0112] In this embodiment, a deposition chamber that has the
structure shown in FIG. 2A is provided as the deposition chamber
A503 for fabrication of the first organic compound layer which
emits red light. Additionally provided as the evaporation sources
are a first evaporation source provided with an organic compound
with hole injectability, a second evaporation source provided with
an organic compound with hole transportability, a third evaporation
source provided with an organic compound with hole transportability
for use as a host of organic compound with luminescent ability, a
fourth evaporation source provided with an organic compound with
luminescent ability, a fifth evaporation source provided with an
organic compound with blocking ability, and a sixth evaporation
source provided with an organic compound with electron
transportability.
[0113] It is also noted that in this embodiment, copper
phthalocyanine (abbreviated as "Cu--Pc" hereinafter) is used as the
organic compound with hole injectability that provided in the first
evaporation source; 4,4'-bis
[N-(1-naphthyl)-N-phenyl-amino]-biphenyl (abbreviated as "o-NPD"
hereafter) is used as the organic compound with hole
transportability being provided in the second evaporation source;
4,4'-dicarbazole-bipheny- l ("CBP") is used as the organic compound
which becomes the host provided in the third evaporation source: 2,
3, 7, 8, 12, 13, 17. 18-octaethyl-21H, 23H-porphyrin-platinum
("PtOEP") is used as the organic compound with luminescent ability
provided in the fourth evaporation source; bathocuproin ("BCP") is
used as the organic compound with blocking ability provided in the
fifth evaporation source; and, tris (8-quinolinolat) aluminum
("Alq.sub.3") is used as the organic compound with electron
transportability provided in the sixth evaporation source.
[0114] It is noted that the organic compound layer comprising
regions having the functions of hole injectability, hole
transportability, luminescent ability, and electron
transportability can be formed over the anode by depositing these
organic compound in order through a vacuum evaporation.
[0115] Also note that in this embodiment, a mixed region is formed
at an interface between different function regions by simultaneous
vacuum evaporation of organic compounds consisting of both function
regions. To be brief, mixed regions are formed respectively at an
interface between the hole injection region and the hole transport
region and at an interface between the hole transport region and
the electron transport region including a luminescent region.
[0116] Practically, after formed a first function region through
deposition of Cu--Pc to a thickness of 15 nm, both Cu--Pc and
.alpha.-NPD are deposited by a vacuum evaporation at a same time to
thereby form a first mixed region with a film thickness of 5 to 10
nm. Then, fabricate a film of .alpha.-NPD to a thickness of 40 nm
to thereby form a second function region, followed by formation of
a second mixed region with a thickness of 5 to 10 nm by
simultaneous vacuum evaporation of .alpha.-NPD and CBP. Thereafter,
fabricate a film of CBP to a thickness of 25 to 40 nm, thus forming
a third function region. At the step of forming the third function
region, both CBP and PtOEP are deposited at a same time, thereby
forming a third mixed region at the entirety or part of the third
function region. Note here that the third mixed region has
luminescent ability. Further, both CBP and BCP are deposited by
simultaneous vacuum evaporation to a film thickness of 5 to 10 nm,
thereby forming a fourth mixed region. In addition, a BCP film is
fabricated to a thickness of 8 nm, thus forming a fourth function
region. Furthermore, BCP and Alq.sub.3 are deposited by
simultaneous vacuum evaporation to a film thickness of 5 to 10 nm,
resulting in formation of a fifth mixed region. Lastly a film of
Alq.sub.3 is formed to a thickness of 25 nm, thus enabling
formation of a fifth function region. With the above process steps,
a first organic compound layer is thus formed.
[0117] It should be noted that in the above explanation concerning
the first organic compound layer six kinds of organic compounds
different in function from one another are provided in six
evaporation sources respectively and the organic compound layer is
then formed by vacuum evaporation of these organic compounds. The
present invention should not be limited only to the above and may
use a plurality of organic compounds. Additionally the organic
compound provided in a single evaporation source should not always
be limited to a single one and may alternatively be multiple ones.
For example, in addition to a single kind of material provided in
an evaporation source as an organic compound with luminescent
ability, another organic compound that serve as a dopant may be
provided together. Note that the first organic compound layer has a
plurality of functions and prior known materials may be used as
these organic compounds composing an organic compound layer which
emits the red light.
[0118] It is to be noted that the evaporation sources may be
designed so that a microcomputer is used to control the deposition
speeds thereof. Additionally, with this arrangement, it is
preferable to control the ratio of mixture upon simultaneous
fabrication of a plurality of organic compound layers.
[0119] Next, the one indicated by numeral 506 is an alignment
chamber. Here. alignment of a metal mask and positioning of a
substrate on the metal mask are done for deposition at a deposition
chamber to which it will next be transferred. This will be called
an alignment chamber B506. Additionally, the method explained in
FIGS. 4A through 4E may be employed in the alignment method here.
Additionally the alignment chamber B506 comprises a gas exhaust
system 500d and is shut and shielded from the deposition chamber
A503 by a gate not shown. It further comprises a cleaning
preliminary chamber 513c that is shut and shielded from the
alignment chamber B506 by a gate not shown, in a similar way to the
alignment chamber A502.
[0120] Next, numeral 507 denotes a deposition chamber for
fabrication of a second organic compound layer by vacuum
evaporation , which will be called the deposition chamber B507.
This deposition chamber B507 is provided with an exhaust system
500e. In addition it is shut and shielded from the alignment
chamber B506 by a gate. not shown. Further, it comprises a cleaning
preliminary chamber 513d which is shut and shielded from the
deposition chamber B507 by a gate not shown, in a similar way to
the deposition chamber A503.
[0121] In this embodiment a deposition chamber with the structure
shown in FIG. 2A is provided as the deposition chamber B507 for
fabrication of a second organic compound layer which emits green
light. Additionally provided as the evaporation sources are a first
evaporation source provided with an organic compound with hole
injectability, a second evaporation source and a third evaporation
source each provided with organic compounds with hole
transportability, a fourth evaporation source provided with a host
material with hole transportability, a fifth evaporation source
provided with an organic compound with luminescent ability, a sixth
evaporation source provided with an organic compound with blocking
ability, and a seventh evaporation source provided with an organic
compound with electron transportability.
[0122] It is noted that in this embodiment, Cu--Pc is employed as
the organic compound with hole injectability provided in the first
evaporation source; MTDATA is employed as the organic compound with
hole transportability provided in the second evaporation source;
.alpha.-NPD is employed as the organic compound with hole
transportability provided in the third evaporation source; CBP is
employed as the host material with hole transportability provided
in the fourth evaporation source; tris (2-phenylpyridine) iridium
(Ir(ppy).sub.3) is employed as the organic compound with
luminescent ability provided in the fifth evaporation source; BCP
is employed as the organic compound with blocking ability provided
in the sixth evaporation source; and, Alq.sub.3 is employed as the
organic compound with electron transportability provided in the
seventh evaporation source.
[0123] It is noted the second organic compound layer can be formed
over the anode by successive vacuum evaporation of these organic
compounds, which comprises regions having functions of hole
transportability, luminescent ability, blocking ability and
electron transportability.
[0124] Also note that in this embodiment, a mixed region is formed
at an interface between different function regions by simultaneous
vacuum evaporation of organic compounds forming both the function
regions. More specifically, mixed regions are formed respectively
at an interface between the hole transport region and the blocking
region and at an interface between the blocking region and the
electron transport region.
[0125] Practically, after formed a first function region through
deposition of Cu--Pc to a thickness of 10 nm, both Cu--Pc and
MTDATA are deposited by a vacuum evaporation at a same time to
thereby form a first mixed region with a film thickness of 5 to 10
nm. Then, fabricate a film of MTDATA to a thickness of 20 nm to
thereby form a second function region, followed by formation of a
second mixed region with a thickness of 5 to 10 nm by simultaneous
vacuum evaporation of MTDATA and .alpha.-NPD. Thereafter fabricate
a film of .alpha.-NPD to a thickness of 10 nm, thereby forming a
third function region. Then, by simultaneous vacuum evaporation of
.alpha.-NPD and CBP, a third mixed region is formed in thickness
from 5 to 10 nm. Subsequently, fabricate a film of CBP to a
thickness of 20 to 40 nm to thereby form a fourth function region.
At the step of forming the fourth function region, (Ir(ppy).sub.3)
is deposited by simultaneous vacuum evaporation at part or entirety
of the fourth function region, thus forming a fourth mixed region;
then, simultaneously deposited CBP and BCP by vacuum evaporation to
form a fifth mixed region with a thickness of 5 to 10 nm; next,
deposit a BCP film of 10-nm thickness to thereby form a fifth
function region; next, simultaneously deposit BCP and Alq.sub.3 by
vacuum evaporation to form a sixth mixed region with a film
thickness of 5 to 10 nm; lastly, form a film of Alq.sub.3 to a
thickness of 40 nm, thus forming a sixth function region to thereby
form a second organic compound layer.
[0126] Noted that in the above explanation the organic compound
layer is formed by vacuum evaporation from seven evaporation
sources provided with organic compounds having different functions
respectively as the second organic compound layer. The present
invention should not be limited only to the above and is modifiable
as far as a plurality of evaporation sources. Additionally prior
known materials may be used as organic compounds with a plurality
of functions for forming an organic compound layer which emits
green light.
[0127] Next, the one indicated by numeral 508 is an alignment
chamber. Here. alignment of a metal mask and positioning of a
substrate on the metal mask are done for deposition at a deposition
chamber to which it will next be transferred. This will be called
an alignment chamber C508. Additionally, the method explained in
FIGS. 4A through 4E may be employed in the alignment method here.
Additionally the alignment chamber C508 comprises a gas exhaust
system 500f and is shut and shielded from the deposition chamber
B507 by a gate not shown. It further comprises a cleaning
preliminary chamber 513e that is shut and shielded from the
alignment chamber C508 by a gate not shown, in a similar way to the
alignment chamber A502.
[0128] Next, numeral 509 denotes a deposition chamber for
fabrication of a second organic compound layer by vacuum
evaporation , which will be called the deposition chamber C509.
This deposition chamber C509 is provided with an exhaust system
500g. In addition it is shut and shielded from the alignment
chamber C508 by a gate not shown. Further, it comprises a cleaning
preliminary chamber 513f which is shut and shielded from the
deposition chamber C509 by a gate not shown, in a similar way to
the alignment chamber A503.
[0129] In this embodiment a deposition chamber with the structure
shown in FIG. 2A is provided as the deposition chamber C509 for
fabrication of a third organic compound layer which emits blue
light. Additionally provided as the evaporation sources are a first
evaporation source provided with an organic compound with hole
injectability, a second evaporation source provided with organic
compound with luminescent ability a third evaporation source
provided with blocking ability, a fourth evaporation source
provided with an organic compound with electron transportability.
It is noted that in this embodiment, Cu--Pc is employed as the
organic compound with hole injectability provided in the first
evaporation source; .alpha.-NPD is employed as the organic compound
with luminescent ability provided in the second evaporation source;
BCP is employed as the organic compound with blocking ability
provided in the third evaporation source; and, Alq.sub.3 is
employed as the organic compound with electron transportability
provided in the fourth evaporation source.
[0130] It is noted the third organic compound layer can be formed
over the anode by successive vacuum evaporation of these organic
compounds, which comprises regions having functions of hole
injectability, luminescent ability, blocking ability and electron
transportability.
[0131] Also note that in this embodiment, a mixed region is formed
at an interface between different function regions by simultaneous
vacuum evaporation of organic compounds forming both the function
regions. More specifically, mixed regions are formed respectively
at an interface between the luminescent region and the blocking
region and at an interface between the blocking region and the
electron transport region.
[0132] Practically, after formed a first function region through
deposition of Cu--Pc to a thickness of 20 nm, both Cu--Pc and
.alpha.-NPD are deposited by a vacuum evaporation at a same time to
thereby form a first mixed region with a film thickness of 5 to 10
nm. Then, fabricate a film of .alpha.-NPD to a thickness of 40 nm
to thereby form a second function region, followed by formation of
a second mixed region with a thickness of 5 to 10 nm by
simultaneous vacuum evaporation of .alpha.-NPD and BCP. Thereafter
fabricate a film of BCP to a thickness of 10 nm, thereby forming a
third function region. Then, by simultaneous vacuum evaporation of
BCP and Alq.sub.3, a third mixed region is formed in thickness from
5 to 10 nm; lastly, form a film of Alq.sub.3 to a thickness of 40
nm, to thereby form a third organic compound layer.
[0133] Noted that in the above explanation the organic compound
layer is formed by successive vacuum evaporation from fourth
evaporation sources provided with four organic compounds having
different functions respectively as the third organic compound
layer. The present invention should not be limited only to the
above and is modifiable as far as a plurality of evaporation
sources. Also, an organic compound provided in a single evaporation
source is not limited to have one kind, may be a plurality of ones.
For instance, in addition to a single kind of material provided in
an evaporation source as the organic compound with luminescent
ability, another organic compound that serve as a dopant may be
provided together. Note that prior known materials may be used as
organic compounds with a plurality of functions for forming an
organic compound layer which emits blue light.
[0134] Additionally in this embodiment, one specific case has been
explained where the organic compound layer which emits red light is
formed in the first deposition chamber A503 while forming the
organic compound layer which emits green light in the second
deposition chamber B507 and also forming the organic compound layer
which emits blue light in the third deposition chamber C509.
However, the order of formation of these layers should not be
limited only the above order. One of the organic compound layers
which emit lights of red, green, and blue, respectively may be
formed within one of the deposition chamber A503, deposition
chamber B507, and deposition chamber C509. Still alternatively, an
additional deposition chamber may be provided for forming an
organic compound layer which emits white light therein. Next,
numeral 510 denotes a deposition chamber for formation of a
conductive film being either the anode or the cathode of a
luminescent element (a metal film used as the cathode in this
embodiment) by vacuum evaporation, which will be called the
deposition chamber D510. The deposition chamber D510 comprises an
exhaust system 500h, in addition, is shut and shielded from the
deposition chamber C509 by a gate not shown. Further, it comprises
a cleaning preliminary chamber 513c which is sealed and shielded
from the deposition chamber D510 by a gate not shown, in a similar
manner to that of the deposition chamber A503.
[0135] In this embodiment a deposition chamber with the structure
shown in FIG. 2A is provided as the deposition chamber D510.
Accordingly, in regard to a detailed operation of the deposition
chamber D510, refer to the explanation of FIG. 2A.
[0136] In this embodiment, in the deposition chamber D510, an
Al--Li alloy film (film made of an alloy of aluminum and lithium)
is deposited as the conductive film used as the cathode of the
luminescent element. Additionally it will also possible to employ
co-vacuum evaporation of aluminum and an element belonging to
either the group I or group II of the periodic table.
[0137] Alternatively a CVD chamber may be provided here for
formation of an insulating film such as a silicon nitride film,
silicon oxide film and DLC film or else as a protective film
(passivation film) of the luminescent element. Note that in the
case of providing such CVD chamber, it will be preferable that a
gas purifying machine be provided for increasing in advance the
purity of a material gases used in the CVD chamber.
[0138] Next, numeral 511 denotes a sealing chamber, which comprises
an exhaust system 500i. In addition, it is shut and shielded from
the deposition chamber D510 by a gate not shown. In the seal
chamber 511, processing is to be done for finally enclosing a
luminescent element in a sealed space. This processing is the
treatment for protecting the luminescent element formed against
oxygen and water, and employs a means for mechanically enclosing it
by a cover material or alternatively for enclosing it by either
thermally hardenable resin or ultraviolet-ray hardenable resin
material.
[0139] While the cover material used may be glass, ceramics,
plastic or metal, the cover material must have optical
transmissivity in cases where light is emitted toward the cover
material side. Additionally the cover material and a substrate with
the above-stated luminescent element formed thereon are adhered
together by use of a seal material such as thermal hardenable resin
or ultraviolet-ray hardenable resin or else, thereby forming an
air-tight sealed space by letting the resin be hardened through
thermal processing or ultraviolet ray irradiation processing. It is
also effective to provide in this sealed space a moisture
absorbable material, typical example of which is barium oxide.
[0140] It will also be possible to fill the space between the cover
material and the substrate having the luminescent element formed
thereon with either thermal hardenable resin or ultraviolet-ray
hardenable resin. In this case, it is effective to add a moisture
absorption material typically such as barium oxide into either the
thermal hardenable resin or ultraviolet-ray hardenable resin.
[0141] In the deposition apparatus shown in FIG. 5, a mechanism for
irradiation of ultraviolet light to the interior of the seal
chamber 511 (referred to as the "ultraviolet light irradiation
mechanism" hereinafter) is provided, which is arranged so that
ultraviolet light as emitted from this ultraviolet light
irradiation mechanism is used to harden the ultraviolet-ray
hardenable resin.
[0142] Lastly, numeral 512 is an unload chamber, which comprises an
exhaust system 500j. The substrate with luminescent element formed
thereon will be taken out of here.
[0143] Further, the deposition apparatus indicated in this
embodiment may be provided with a function of enabling replacement
of an organic compound as shown in FIGS. 6A and 6B. In FIGS. 6A and
6B, a deposition chamber 601 comprises a substrate 602. And an
organic compound for formation of an organic compound layer on the
substrate is provided in an evaporation source 603. Note that,
here, a evaporation source 603 is provided in a material exchange
chamber 604 separated from the deposition chamber 601 with the
substrate furnished therein through a gate 605. Accordingly, in
this embodiment, the material exchange chamber 604 is separated
from the deposition chamber 601 by closure of the gate 605, organic
compounds furnished in the evaporation source of the material
exchange chamber 604 can be added or exchange by returning the
interior of the material exchange chamber 604 to an atmospheric
pressure via an exhaust system 606 and then taking the organic
compounds out as shown in FIG. 6A.
[0144] And, after finished addition or exchange of the organic
compounds, the material exchange chamber 604 is returned to its
original state again as shown in FIG. 6B, then, interior of the
material exchange chamber 604 is set in a vacuum state by the
exhaust system 606, and, after it has become the same pressure
condition as the interior of deposition chamber, open the gate 605.
Thus it is possible of vacuum evaporation from the evaporation
source 603 to the substrate 602.
[0145] Note that the material exchange chamber 604 is provided with
a heater for heating the material thus exchanged. Preheating the
material makes it possible to remove away impurities such as water
or the like. It will be desirable that a temperature applied at
this time be equal to or less than 200.degree. C.
[0146] As described the above, by using the deposition apparatus
shown in FIG. 5 (or FIGS. 6A and 6B), exposure of the luminescent
element to the outside air is avoided until the luminescent element
is completely enclosed in the sealed space. Thus, it is possible to
manufacture a luminescent device with high reliability.
[0147] [Embodiment 2]
[0148] A deposition apparatus of the present invention will be
explained with reference to FIGS. 7A and 7B. In FIGS. 7A and 7B,
reference numeral 701 denotes a transfer chamber, wherein this
transfer chamber 701 comprises a transfer mechanism A702 for
performing transport of a substrate 703. The transfer chamber 701
is set in a pressure-reduced atmosphere and is coupled by a gate
with each processing chamber. A substrate is transported to each
processing chamber by the transfer mechanism A702 upon opening of
the gate. Additionally while exhaust pump such as a dry pump, a
mechanical booster pump, a turbo molecular pump (magnetic
floatation type) or cryopump is employable for pressure reduction
of the transfer chamber 701, the turbo molecular pump of the
magnetic flotation type is preferable in order to obtain
high-degree vacuum states with higher purity.
[0149] An explanation will be given of each processing chamber
below. Note that the transfer chamber 701 is set in a
pressure-reduced atmosphere so that all the processing chambers
directly coupled to the transfer chamber 701 are provided with
vacuum pumps (not shown). While dry pumps, mechanical booster
pumps, turbo molecular pumps (magnetic floatation type) or
cryopumps are employable as the vacuum pumps, the turbo molecular
pumps of the magnetic flotation type are preferable in this case
also. First, numeral 704 denotes a load chamber for performing
setting (installation) of a substrate. The load chamber 704 is
coupled by a gate 700a with the transfer chamber 701, at here a
carrier (not shown) with a substrate 703 mounted thereon is
arranged. Additionally the load chamber 704 can also do double-duty
as a chamber that transfers a substrate which element formation is
finished toward the sealing chamber. Additionally the load chamber
704 may alternatively have separated rooms for carry-in of the
substrate and for carry-out of the substrate. Note that the load
chamber 704 comprises the above described vacuum pomp and a purge
line for introduction of a high-purity nitride gas or noble gas.
Additionally the vacuum pump used herein is preferably a turbo
molecular pump. Further, this purge line is provided with a gas
refining machine for removal in advance of impurities (oxygen and
water) of such gases to be introduced into the apparatus.
[0150] It is also noted that in this embodiment, a substrate which
a transparent conductive film used as the anode of luminescent
element is formed thereon is used as the substrate 703. In this
embodiment the substrate 703 is set in a carrier with its
deposition surface being directed downwardly. This is for
performing of face-down scheme (also known as "depo-up" scheme)
when later performing deposition by vacuum evaporation methods. The
face-down scheme is to be understood to mean a scheme for
performing deposition while letting the deposition surface of a
substrate being directed downwardly. With this scheme, it is
possible to suppress attachment of contaminant particles such as
dusts.
[0151] Next, the one indicated by numeral 705 is an alignment
chamber for alignment of a metal mask and for matching position
between a metal mask and a substrate with either the anode or the
cathode of luminescent element (anode in this embodiment) formed
thereon, wherein the alignment chamber 705 is coupled by a gate
700b with the transfer chamber 701. Note that a process in
combination of the metal mask alignment and positioning of the
substrate and metal mask is done within the alignment chamber, once
at a time whenever a different organic compound layer is formed. In
addition, the alignment chamber 705 comprises a charge-coupled
device (CCD) known as an image sensor, thereby making it possible
to accurately perform position alignment of the substrate and its
associated metal mask in deposition using the metal mask. Note that
with respect to metal mask alignment, the method discussed in FIGS.
4A through 4E may be used.
[0152] Further, a cleaning preliminary chamber 722a is coupled to
the alignment chamber 705. An arrangement of the cleaning
preliminary chamber 722a is as shown in FIG. 7B. First, the
cleaning preliminary chamber 722a has a .mu. wave oscillator 731
for generation of .mu. waves, wherein .mu. waves generated at here
will be sent through a wave guide tube 732 toward a plasma
discharge tube 733. Note that .mu. waves of about 2.45 GHz are
radiated from the .mu. wave oscillator 731 used here. In addition,
a reactive gases are supplied to the plasma discharge tube 733 from
a gas inlet tube 734. Additionally here, NF.sub.3 is used as the
reactive gas, although other gases such as CF.sub.4 and ClF.sub.3
may be used as reactive gases.
[0153] And, the reactive gas is decomposed by .mu. wave in the
plasma discharge tube 733, causing radicals to generate. These
radicals are guided to pass through the gas inlet tube 734 to
introduce the alignment chamber 705 as coupled via a gate (not
shown) thereto. Additionally the plasma discharge tube 733 may be
provided with a reflection plate 735 for efficient supplement of
.mu. waves.
[0154] And, the alignment chamber 705 comprises a metal mask with
an organic compound layer attached thereto. And open a gate (not
shown) provided between the cleaning preliminary chamber 722a and
the alignment chamber 705, thereby enabling introduction of
radicals into the alignment chamber 705. This makes it possible to
perform cleaning of the metal mask.
[0155] As the use of L-wave plasma makes it possible to perform
radicalization of a reactive gas with high efficiency, the rate of
creation of impurities such as side products or the like is low. In
addition, since it is different in mechanism from standard radical
production, the resultant radicals will no longer be accelerated
and radical is not produced within the interior of the deposition
chamber. This makes it possible to prevent damages within the
deposition chamber due to the presence of a plasma and also damages
of the metal mask.
[0156] It should be noted that the technique for cleaning the
alignment chamber by use of the thus method is one of the preferred
modes of the present invention so that this invention should not be
limited thereto. Accordingly, it may also be performed a dry
cleaning by introducing reactive gases into the deposition chamber
to thereby produce a plasma within this deposition chamber,
alternatively, a physical cleaning by sputter methods through
introduction of an Ar gas or else.
[0157] Next, numeral 706 denotes a deposition chamber used for
deposition of an organic compound layer by vacuum evaporation
method, which will be called the deposition chamber A706
hereinafter. The deposition chamber A706 is coupled via a gate 700c
to the transfer chamber 701. In this embodiment a deposition
chamber with the structure shown in FIG. 2A is provided as the
deposition chamber A706.
[0158] With this embodiment, a first organic compound layer capable
of emitting red light is formed at a deposition unit 707 within the
deposition chamber A706. A plurality of evaporation sources are
provided with the deposition chamber A706, practically, there are
provided a first evaporation source comprising an organic compound
material with hole injectability, a second evaporation source
comprising an organic compound with hole transportability, a third
evaporation source comprising an organic compound with luminescent
ability, and a fourth evaporation source comprising an organic
compound with electron transportability.
[0159] Note that by successive vacuum evaporation of these organic
compounds sequential vacuum evaporation, the organic compound layer
can be formed above the anode, which comprises regions having
functions of hole injectability, hole transportability, luminescent
ability and electron transportability.
[0160] Additionally in this embodiment, a mixed region is formed at
an interface between different function regions by simultaneous
vacuum evaporation of organic compounds forming such both function
regions. More specifically, several mixed regions are formed at an
interface between the hole injection region and the hole transport
region, at an interface between the hole transport region and the
luminescent region, and at an interface between the luminescent
region and electron transport region, respectively.
[0161] Noted that in the above explanation the organic compound
layer is formed by successive vacuum evaporation from four
evaporation sources provided with four organic compounds having
different functions respectively as the first organic compound
layer. The present invention should not be limited only to the
above and is modifiable as far as a plurality of evaporation
sources. Also, an organic compound provided in a single evaporation
source is not limited to have one kind, may be a plurality of ones.
For instance, in addition to a single kind of material provided in
an evaporation source as the organic compound with luminescent
ability, another organic compound that serve as a dopant may be
provided together. Additionally, as the organic compounds having
the plurality of functions and forming the organic compound layer
which emits red light, the ones as indicated in Embodiment 1 is
employable, although known materials are freely used in combination
where necessary.
[0162] It is also noted that the deposition chamber A706 is coupled
via a gate 700g to a material exchange chamber 714. Also note that
the material exchange chamber 714 is provided with a heater for
heating organic compounds exchanged. Preheating such organic
compounds makes it possible to remove impurities such as water or
the like. It will be desirable that a temperature being applied
here be 200.degree. C. or below. In addition, since the material
exchange chamber 714 is provided with a vacuum pump capable of
setting its interior in a pressure reduction, let the interior be
set in such vacuum pressure state after heat up processing by
addition or exchange of an organic compound from the outside. And,
when it becomes the same pressure state as that within the
deposition chamber, open the gate 700g to thereby enable the
evaporation source within the deposition chamber to be provided
with an organic compound. Additionally the organic compound is
provided at the evaporation source within the deposition chamber by
means of a transfer mechanism.
[0163] Additionally, regarding the deposition process within the
deposition chamber A706, refer to the explanation of FIG. 2A.
[0164] Note that in a similar way to the alignment chamber 705, a
cleaning preliminary chamber 722b is coupled to the deposition
chamber A706 via a gate (not shown). Additionally its practical
arrangement is similar to that of the cleaning preliminary chamber
722a, thus, it is possible by introducing radicals generated in the
cleaning preliminary chamber 722b into the deposition chamber A706
to remove organic compounds and the like being internally attached
to the deposition chamber A706.
[0165] Next, numeral 708 denotes a deposition chamber used for
deposition of a second organic compound layer by vacuum evaporation
method, which will be called the deposition chamber B708
hereinafter. The deposition chamber B708 is coupled via a gate 700d
to the transfer chamber 701. In this embodiment a deposition
chamber with the structure shown in FIG. 2A is provided as the
deposition chamber B708. With this embodiment, the second organic
compound layer capable of emitting green light is formed at a
deposition unit 709 within the deposition chamber B708.
[0166] A plurality of evaporation sources are provided with the
deposition chamber B708, practically, there are provided a first
evaporation source comprising an organic compound with hole
transportability, a second evaporation source comprising an organic
compound with luminescent ability, a third evaporation source
comprising an organic compound with blocking ability, and a fourth
evaporation source comprising an organic compound with electron
transportability.
[0167] Note that sequential vacuum evaporation of these organic
compounds makes it possible to form on the anode an organic
compound layer consisting essentially of regions having functions
of hole transportability, luminescent ability, blocking ability and
electron transportability.
[0168] Additionally in this embodiment, a mixed region is formed at
an interface between different function regions by simultaneous
vacuum evaporation of organic compounds forming such both function
regions. More specifically, several mixed regions are formed at an
interface between the hole transport region and the luminescent
region, at an interface between the luminescent region and the
blocking region, and at an interface between the blocking region
and electron transport region, respectively.
[0169] Noted that in the above explanation the organic compound
layer is formed by successive vacuum evaporation from four
evaporation sources provided with four organic compounds having
different functions respectively as the second organic compound
layer. The present invention should not be limited only to the
above and is modifiable as far as a plurality of evaporation
sources. Also, an organic compound provided in a single evaporation
source is not limited to have one kind, may be a plurality of ones.
For instance, in addition to a single kind of material provided in
an evaporation source as the organic compound with luminescent
ability, another organic compound that serve as a dopant may be
provided together. Additionally, as the organic compounds having
the plurality of functions and forming the organic compound layer
which emits green light, the ones as indicated in Embodiment 1 is
employable. although known materials are freely used in combination
where necessary.
[0170] It is also noted that the deposition chamber B708 is coupled
via a gate 700h to a material exchange chamber 715. Also note that
the material exchange chamber 715 is provided with a heater for
heating organic compounds exchanged. Preheating such organic
compounds makes it possible to remove impurities such as water or
the like. It will be desirable that a temperature being applied
here be 200.degree. C. or below. In addition, since the material
exchange chamber 715 is provided with a vacuum pump so that after
introducing organic compounds from the outside it is possible to
set its interior in a pressure reduction by the vacuum pump. And,
when it becomes the same pressure state as that within the
deposition chamber, open the gate 700h to thereby enable the
evaporation source within the deposition chamber to be provided
with an organic compound. Additionally the organic compound is
provided at the evaporation source within the deposition chamber by
means of a transfer mechanism.
[0171] Additionally, regarding the deposition process within the
deposition chamber B708, refer to the explanation of FIG. 2A.
[0172] Note that in a similar way to the alignment chamber 705, a
cleaning preliminary chamber 722c is coupled to the deposition
chamber B708 via a gate (not shown). Additionally its practical
arrangement is similar to that of the cleaning preliminary chamber
722a, thus, it is possible by introducing radicals generated in the
cleaning preliminary chamber 722c into the deposition chamber B708
to remove organic compounds and the like being internally attached
to the deposition chamber B708.
[0173] Next, numeral 710 denotes a deposition chamber used for
deposition of a third organic compound layer by vacuum evaporation
method, which will be called the deposition chamber C710
hereinafter. The deposition chamber C710 is coupled via a gate 700e
to the transfer chamber 701. In this embodiment a deposition
chamber with the structure shown in FIG. 2A is provided as the
deposition chamber C710. With this embodiment, the third organic
compound layer capable of emitting blue light is formed at a
deposition unit 711 within the deposition chamber C710.
[0174] A plurality of evaporation sources are provided with the
deposition chamber C710, practically, there are provided a first
evaporation source comprising an organic compound with hole
injectability, a second evaporation source comprising an organic
compound with luminescent ability, a third evaporation source
comprising an organic compound with blocking ability, and a fourth
evaporation source comprising an organic compound with electron
transportability.
[0175] Note that sequential vacuum evaporation of these organic
compounds makes it possible to form on the anode an organic
compound layer consisting essentially of regions having functions
of hole injectablity, luminescent ability, blocking ability and
electron transportability.
[0176] Additionally in this embodiment, a mixed region is formed at
an interface between different function regions by simultaneous
vacuum evaporation of organic compounds forming such both function
regions. More specifically, several mixed regions are formed at an
interface between the hole injection region and the luminescent
region, at an interface between the luminescent region and the
blocking region, and at an interface between the blocking region
and electron transport region, respectively.
[0177] Noted that in the above explanation the organic compound
layer is formed by successive vacuum evaporation from four
evaporation sources provided with four organic compounds having
different functions respectively as the third organic compound
layer. The present invention should not be limited only to the
above and is modifiable as far as a plurality of evaporation
sources. Also, an organic compound provided in a single evaporation
source is not limited to have one kind, may be a plurality of ones.
For instance, in addition to a single kind of material provided in
an evaporation source as the organic compound with luminescent
ability, another organic compound that serve as a dopant may be
provided together. Additionally, as the organic compounds having
the plurality of functions and forming the organic compound layer
which emits blue light, the ones as indicated in Embodiment 1 is
employable, although known materials are freely used in combination
where necessary.
[0178] It is also noted that the deposition chamber C710 is coupled
via a gate 700i to a material exchange chamber 716. Also note that
the material exchange chamber 715 is provided with a heater for
heating organic compounds exchanged. Preheating such organic
compounds makes it possible to remove impurities such as water or
the like. It will be desirable that a temperature being applied
here be 200.degree. C. or below. In addition, since the material
exchange chamber 716 is provided with a vacuum pump so that after
introducing organic compounds from the outside it is possible to
set its interior in a pressure reduction by the vacuum pump. And,
when it becomes the same pressure state as that within the
deposition chamber, open the gate 700i to thereby enable the
evaporation sources within the deposition chamber to be provided
with organic compounds. Additionally the organic compound is
provided at the evaporation source within the deposition chamber by
means of a transfer mechanism. Additionally, regarding the
deposition process within the deposition chamber C710, refer to the
explanation of FIG. 2A.
[0179] Note that in a similar way to the alignment chamber 705, a
cleaning preliminary chamber 722d is coupled to the deposition
chamber C710 via a gate (not shown). Additionally its practical
arrangement is similar to that of the cleaning preliminary chamber
722a, thus, it is possible by introducing radicals generated in the
cleaning preliminary chamber 722d into the deposition chamber C710
to remove organic compounds and the like being internally attached
to the deposition chamber C710.
[0180] Next, numeral 712 indicates a deposition chamber for
fabricating by vacuum evaporation method a conductive film used as
either the anode or cathode of a luminescent element (in this
embodiment, a metal film used as the cathode), which chamber will
be called the deposition chamber D712. This deposition chamber D712
is coupled via a gate 700f to the transfer chamber 701. In this
embodiment, at the deposition unit 713 within the deposition
chamber D712, an Al--Li alloy film (alloy film of aluminum and
lithium) is to be formed as the conductive film used as the cathode
of the luminescent element. It will also be possible to perform
co-vacuum evaporation of both aluminum and an element belonging to
either the group I or group II of the periodic table at a time. The
term co-vacuum evaporation refers to a vacuum evaporation method
that evaporation sources are heated simultaneously and different
materials are mixed together at the deposition step.
[0181] It is also noted that the deposition chamber D712 is coupled
via a gate 700j to a material exchange chamber 717. Also note that
the material exchange chamber 717 is provided with a heater for
heating organic compounds exchanged. Preheating such organic
compounds makes it possible to remove impurities such as water or
the like. It will be desirable that a temperature being applied
here be 200.degree. C. or below. In addition, since the material
exchange chamber 717 is provided with a vacuum pump so that after
introducing conductive materials from the outside it is possible to
set its interior in a pressure reduction by the vacuum pump. And,
when it becomes the same pressure state as that within the
deposition chamber, open the gate 700j to thereby enable the
evaporation sources within the deposition chamber to be provided
with conductive materials.
[0182] Note that in a similar way to the alignment chamber 705, a
cleaning preliminary chamber 722e is coupled to the deposition
chamber D712 via a gate (not shown). Additionally its practical
arrangement is similar to that of the cleaning preliminary chamber
722a, thus, it is possible by introducing radicals generated in the
cleaning preliminary chamber 722e into the deposition chamber D712
to remove conductive materials and the like being internally
attached to the deposition chamber D712.
[0183] In addition a respective one of the deposition chamber A706,
the deposition chamber B708, the deposition chamber C710 and
deposition chamber D712 comprises a mechanism for heating the
interior of each deposition chamber. Whereby it is possible to
remove part of impurities in the deposition chambers.
[0184] Further note that although dry pumps, mechanical booster
pumps, turbo molecular pumps (magnetic floatation type) or
cryopumps are employable as the vacuum pumps provided in these
deposition chambers, it is desirable that the cryopumps and dry
pumps be used in this embodiment.
[0185] In addition, the deposition chamber A706, the deposition
chamber B708, the deposition chamber C710 and deposition chamber
D712 are reduced in pressure by the vacuum pumps. It is desirable
that the finally reached degree of vacuum at this time be greater
than or equal to 10.sup.-6 Pa. For example, with the use of a
cryopump with its evacuation rate of 10,000 l/s (H.sub.2O), a
leakage amount within a deposition chamber must be less than or
equal to 4.1.times.10.sup.-7 Pa*m.sup.3*s.sup.-1 for 20 hours, when
the interior of the deposition chamber is formed of aluminum while
letting a surface area of the deposition chamber interior measure
10 m.sup.2. In order to obtain such vacuum degree, it is effective
to minimize by electro-polishing techniques the surface area of the
deposition chamber interior.
[0186] Next, numeral 718 denotes a sealing chamber (also known as
an enclosing chamber or "glove box"), which is coupled via a gate
700k to the load chamber 704. In the sealing chamber 718,
processing for finally enclosing a luminescent element into a
sealed space is performed. This processing is for protection of the
formed luminescent element against oxygen and water, which employs
a means for mechanically enclosing by cover material or
alternatively enclosing by using either thermally hardenable resin
or ultraviolet ray hardenable resin material.
[0187] While the cover material used may be glass, ceramics,
plastic or metal, the cover material must have optical
transmissivity in cases where light is emitted toward the cover
material side. Additionally the cover material and a substrate with
the above-stated luminescent element formed thereon are adhered
together by use of a seal material such as thermal hardenable resin
or ultraviolet-ray hardenable resin or else, thereby forming an
air-tight sealed space by letting the resin be hardened through
thermal processing or ultraviolet ray irradiation processing. It is
also effective to provide in this sealed space a moisture
absorbable material, typical example of which is barium oxide.
[0188] It will also be possible to fill the space between the cover
material and the substrate having the luminescent element formed
thereon with either thermal hardenable resin or ultraviolet-ray
hardenable resin. In this case, it is effective to add a moisture
absorption material typically such as barium oxide into either the
thermal hardenable resin or ultraviolet-ray hardenable resin.
[0189] In the deposition apparatus shown in FIG. 7A, a mechanism
719 for irradiation of ultraviolet light to the interior of the
sealing chamber 718 (referred to as the "ultraviolet light
irradiation mechanism" hereinafter) is provided, which is arranged
so that ultraviolet light as emitted from this ultraviolet light
irradiation mechanism 719 is used to harden the ultraviolet-ray
hardenable resin. Attachment of a vacuum pump makes also possible
to reduce pressure within the sealing chamber 718. In case the
above sealing process is done mechanically by robot operation, it
is possible by performing this process to prevent mixture of oxygen
and water because of atmosphere in reduced pressure. Practically it
is desired that the concentrations of such oxygen and water be made
less than or equal to 0.3 ppm. Additionally, it is also possible
that the interior of the seal chamber 718 is pressurized adversely.
In this case, the sealing chamber 718 is purged by a nitride gas or
noble gas of high purity and pressurized, thereby the invasion of
oxygen or the like from the outside is prevented.
[0190] Next, a delivery chamber (pass box) 720 is coupled to the
sealing chamber 718. The delivery chamber 720 is provided with a
transfer mechanism B721 for transferring toward the delivery
chamber 720 a substrate which sealing of the luminescent element is
completed in the sealing chamber 718. The delivery chamber 720)
also can be set in a reduced pressure state by attachment of a
vacuum pump thereto. This delivery chamber 720 is the facility that
prevents the sealing chamber 718 from being exposed directly to the
outside air, from which the substrate is removed. Optionally it is
also possible to provide a member supply chamber (not shown) for
supplying members to be used in the sealing chamber.
[0191] It must be noted that although 'not shown in diagrams of
this embodiment, insulating films with lamination of chemical
compounds including silicon such as silicon nitride or silicon
oxide and with lamination of a diamond like carbon (DLC) film
containing carbon on these chemical compounds may be formed on a
luminescent element after forming the luminescent element.
Additionally the term diamond-like carbon (DLC) film refers to an
amorphous film with a mixture of diamond bonding (sp.sup.3 bond)
and graphite bond (Sp.sup.2 bond). Note that in this case, a
deposition chamber may be provided which comprises a chemical vapor
deposition (CVD) apparatus for generating a plasma by application
of a self bias to thereby form a thin film through plasma discharge
decomposition of material gases.
[0192] Note that in the deposition chamber comprising such chemical
vapor deposition (CVD) apparatus, there may be used oxygen
(O.sub.2), hydrogen (H.sub.2) methane (CH.sub.4), ammonia
(NH.sub.3) and silane (SiH.sub.4). Also note that as the CVD
apparatus, there is employable the one that has electrodes of the
parallel flat-plate type with RF power supply of 13.56 MHz.
[0193] Further, it is also possible to provide a deposition chamber
for performing deposition by sputtering methods (also called
sputter methods). This is due to the fact that deposition by
sputtering is effective in the case of forming the anode after
forming organic compound layers on the cathode of a luminescent
element. In other words, it is effective in cases where a pixel
electrode is the cathode. Additionally the interior of such
deposition chamber is set at an atmosphere with oxygen added to
argon during deposition whereby the concentration of oxygen in a
film thus fabricated is well controlled to enable formation of a
low resistance film that is high in optical transmissivity. Also
note that it will be desirable that the deposition chamber be
shielded by a gate from the transfer chamber in a similar manner to
the remaining deposition chambers.
[0194] It is to be noted that in the deposition chamber for
sputtering, a mechanism may be provided which is operable to
control the temperature of such substrate deposited. Additionally
it is desirable that the substrate deposited be kept at temperature
ranging from 20 to 150.degree. C. Further, although a dry pump,
mechanical booster pump, turbo molecular pump (magnetic floatation
type) or cryopump is useable as a vacuum pump to be provided in the
deposition chamber, the turbo molecular pump (the magnetic
flotation type) and dry pump are preferably employed in this
embodiment.
[0195] As apparent from the foregoing, the use of the deposition
apparatus shown in FIGS. 7A and 7B makes it possible to prevent
exposure of a luminescent element to the outside air until the
luminescent element is completely enclosed in an air-tight sealed
space, which in turn enables successful manufacture of a
luminescent device with high reliability.
[0196] [Embodiment 3]
[0197] In this embodiment, a deposition apparatus will be explained
with reference to FIGS. 8A and 8B, which is different in substrate
transfer method and structure from the deposition apparatus of the
inline type as has been indicated in the embodiment 1.
[0198] In FIGS. 8A and 8B, a substrate 804 as loaded into a load
chamber 800 is transported toward a first alignment unit 801 which
is coupled thereto via a gate (not shown). Note that the substrate
804 is subjected to alignment by the method discussed in FIGS. 4A
through 4E and then fixed to a holder 802 along with a metal mask
803.
[0199] And, the substrate 804 is transferred to a first deposition
unit 805 together with the holder 802. Note here that the first
alignment unit 801 and the first deposition unit 805 are coupled
together via no gates and have the same space. Then, in this
embodiment, a rail 812 is provided as a means for enabling free
movement between the first alignment unit 801 and the first
deposition unit 805, wherein each processing is to be done while
the holder 802 is moving along this rail. Additionally the
processing position during alignment and deposition is controlled
by a control mechanism owned by the holder 802.
[0200] And in the first deposition unit 805, different organic
compounds is deposited by vacuum evaporation from a plurality of
evaporation sources 806 furnished with the organic compounds
respectively to thereby form a first organic compound layer. Note
that this movement means will also be used in the case of transfer
toward a second alignment unit 807 and a second deposition unit 808
for fabrication of a second organic compound layer in a similar way
to that discussed above.
[0201] Further, in the case of forming a third organic compound
also, it is similarly transferred to a third alignment unit 809 and
a third deposition unit 810.
[0202] As discussed above in this embodiment, it is possible to
form three different kinds of organic compound layers within the
same space. The third deposition unit 810 is coupled via a gate
(not shown) to an unload chamber 811, thus enabling unloading of a
substrate with deposition completed.
[0203] It is noted that the processing method at the alignment
units and the deposition units in this embodiment is similar to
that in the alignment and the deposition chambers of the embodiment
1.
[0204] It is also noted that in this embodiment, provision of a
partition wall between the alignment units and the deposition units
makes it possible to prevent organic compounds from dispersing out
of the evaporation sources during deposition toward locations other
than the deposition units.
[0205] In the deposition apparatus of this embodiment also, a
cleaning preliminary chamber 813 may be provided for cleaning of
the interior of each deposition chamber and metal masks.
[0206] Forming a plurality of organic compound layers are formed
within the same space by using the deposition apparatus stated
above, movement between different organic compound layers during
formation, thus making it possible to shorten a time as taken to
complete the processing.
[0207] Note here that while in the deposition apparatus indicated
in this embodiment it is possible to form three kinds of organic
compound layers having a plurality functions on a substrate with
the anode or cathode of a luminescent through continuous vacuum
evaporation processes in the deposition chamber. It is modifiable
that a further deposition chamber for fabrication of a conductive
film is provided for enabling continuous formation of the cathode
or anode of such luminescent element. Additionally in the case of
forming the cathode, the conductive film may be an Al--Li alloy
film (alloy film of aluminum and lithium) or alternatively a film
obtained by co-vacuum evaporation of both aluminum and an element
belonging to either the group I or group II of the periodic table
at a time, in the case of forming the anode, there may be used
indium oxide, tin oxide, zinc oxide, or an alloys of them (such as
ITO).
[0208] In addition to the above, it is also possible to provide a
processing chamber for performing a sealing of the luminescent
element thus manufactured.
[0209] [Embodiment 4]
[0210] In this embodiment an explanation will be given of a
luminescent device manufactured by use of the deposition apparatus
of the present invention. FIG. 9 is a diagram showing a
cross-sectional view of an active matrix type luminescent device.
Note that although thin film transistors (referred to as "TFTs"
hereinafter) are employed as active elements, these are replaceable
by MOS transistors.
[0211] Additionally, although top gate type TFTs (practically
planar type TFTs) will be exemplarily indicated as the TFTs, bottom
gate type TFTs (typically, inverse stagger type TFTs) is
alternatively employable.
[0212] In FIG. 9, numeral 901 denotes a substrate, here, which
permits transmission of visible light rays. Practically, a glass
substrate, a quartz substrate, a crystallized glass substrate or
plastic substrate (including a plastic film) are useable. Note that
the substrate 901 includes an insulating film provided on the
surface thereof.
[0213] A pixel portion 911 and a drive circuit 912 are provided on
the substrate 901. The pixel portion 911 will first be explained
below.
[0214] The pixel portion 911 is a region that performs image
displaying. A plurality of pixels are present on the substrate,
each of which is provided with a TFT 902 for control of a current
flowing in a luminescent element (referred to hereinafter as
current controlling TFT), a pixel electrode (anode) 903, an organic
compound layer 904 and a cathode 905. In addition, numeral 913
denotes a TFT for controlling a voltage applied to the gate of the
current controlling TFT (referred to as switching TFT
hereinafter).
[0215] Preferably here, the current controlling TFT 902 is a
p-channel type TFT. although it may alternatively be an n-channel
TFT, the use of p-channel TFT makes it possible to suppress
consumption of electrical power in case the current controlling TFT
is connected to the anode of the luminescent element as shown in
FIG. 9. Note however that the switching TFT 913 may be either
n-channel TFT or p-channel TFT.
[0216] It is noted that drain of the current controlling TFT 902 is
electrically connected with the pixel electrode 903. In this
embodiment, since the pixel electrode 903 is used a conductive
material with its work function within a range of 4.5 to 5.5 eV,
the pixel electrode 903 functions as the anode of the luminescent
element. The pixel electrode 903 may typically be made of indium
oxide, tin oxide, zinc oxide, or compounds thereof (such as ITO).
The organic compound layer 904 is provided on the pixel electrode
903.
[0217] Further, the cathode 905 is provided on the organic compound
layer 904. It is desirable that the cathode 905 be made of a
conductive material with its work function ranging from 2.5 to 3.5
eV. The cathode 905 is typically made from a conductive film
containing alkaline metal elements or alkali rare metal elements, a
conductive film containing aluminum, and one that aluminum or
silver is laminated on the above conductive films.
[0218] In addition the luminescent element 914 comprising the pixel
electrode 903, the organic compound layer 904, and cathode 905 is
covered with a protective film 906. This protective film 906 is
provided for protection of the luminescent element 914 against
oxygen and water. The protective film 906 is made of material such
as silicon nitride, silicon oxynitride, aluminum oxide, tantalum
oxide or carbon (typically, diamond like carbon).
[0219] An explanation will next be given of the drive circuit 912.
The drive circuit 912 is the region that controls the timing of
signals (gate signal and data signal) being sent to the pixel
portion 911, which is provided with a shift register, a buffer, a
latch, an analog switch (transfer gate), or a level shifter. In
FIG. 9 a CMOS circuit is shown which is made up of an n-channel TFT
907 and p-channel TFT 908 for use as a basic unit of these
circuits.
[0220] The circuit structure of the shift register, the buffer, the
latch, the analog switch transfer gate) or the level shifter may be
designed in a known way. Additionally although in FIG. 9 the pixel
portion 911 and the drive circuit 912 are provided on the same
substrate, it is also possible to electrically connect IC and LSI
without providing the drive circuit 912.
[0221] Additionally, although in FIG. 9 the pixel electrode (anode)
903 is electrically connected to the current controlling TFT 902,
this may be modified into a structure with the cathode connected to
the current controlling TFT. In such case, the pixel electrode 903
may be made of the same material as that of the cathode 905 while
letting the cathode be made of similar material to that of the
pixel electrode (anode) 903. In such case it will be preferable
that the current controlling TFT be an n-channel TFT.
[0222] It is also noted that in this embodiment, a shape with an
cave (called the eave structure hereinafter) consisting essentially
of a wiring line 909 and a separation portion 910 is provided. The
eave structure made of the wiring line 909 and the separation
portion 910 shown in FIG. 9 is manufacturable by a method having
the steps of laminating a metal constituting the wiring line 909
and a material (e.g. metal nitrides) that forms the separation
portion 910 and has a lower etch rate than the metal and then of
etching the same. With use of this shape, it is possible to prevent
the pixel electrode 903 and the wiring line 909 from electrically
shorting with the cathode 905. Additionally in this embodiment,
unlike standard active matrix type luminescent devices, the cathode
905 on a pixel is formed into a stripe shape (in a similar manner
to that of the cathode of a passive matrix).
[0223] Here, an appearance of the active matrix type luminescent
device of FIG. 9 is shown in FIGS. 10A and 10B. Note here that an
upper plan view is shown in FIG. 10A whereas a sectional view taken
along line A-A' of FIG. 10A is shown in FIG. 10B. Additionally the
reference numerals used in FIG. 9 are also used here.
[0224] Numeral 1001 indicated by dotted lines denotes a source side
drive circuit; 1002 denotes a pixel portion; 1003 is a gate side
drive circuit. In addition, 1004 indicates a cover material, and
1005 is a seal material, wherein a space 1007 is provided in
interior part surrounded by the seal material 1005.
[0225] Additionally, numeral 1008 denotes a wiring line which
transfers signal as input to the source side drive circuit 1001 and
gate side drive circuit 1003, which receives a video signal and a
clock signal from a flexible printed circuit (FPC) 1009 for use as
an external input terminal. Note that although the FPC alone is
depicted herein, a printed wiring board (PWB) is attachable to this
FPC. The luminescent device of the subject patent application
includes an IC-mounted luminescent module as well as a luminescent
module with either the FPC or the PWB attached onto a luminescent
panel.
[0226] An explanation will next be given of the sectional structure
with reference to FIG. 10B. The pixel portion 1002 and the gate
side drive circuit 1003 are formed at upper part of the substrate
901, wherein the pixel portion 1002 is formed of a plurality of
pixels each including the current controlling TFT 902 and the pixel
electrode 903 electrically connected to the drain of the current
controlling TFT. Additionally the gate side drive circuit 1003 is
formed using a CMOS circuit with a combination of the n-channel TFT
907 and the p-channel TFT 908. The pixel electrode 903 functions as
the anode of a luminescent element. In addition an interlayer
insulating film 1006 is formed at the opposite ends of the pixel
electrode 903, and the organic compound layer 904 and the cathode
905 of the luminescent element are formed on the pixel electrode
903.
[0227] The cathode 905 also serves as a common wiring line for a
plurality of pixels and is electrically connected via the
connection lead 1008 with the FPC 1009. Further all the elements
involved in the pixel portion 1002 and the gate side drive circuit
1003 are covered with the protective film 906.
[0228] Note that the cover material 1004 is adhered by the seal
material 1005. Additionally a spacer formed of a resin film may be
provided in order to retain a distance between the cover material
1004 and the luminescent element. And an interior of the seal
material 1005 becomes a sealed space, in which a inactive gas such
as nitrogen or argon or else is filled. Optionally it is also be
effective to provide in this sealed space a moisture absorption
material such as barium oxide.
[0229] Note that while a glass, a ceramics, a plastic or metals are
usable as the cover material, it must be optical transmissivity in
the case of irradiating light onto the cover material side.
Additionally fiberglass-reinforced plastics (FRP),
polyvinylfluoride (PVF), Mylar, polyester or acryl is useable as
the plastic material.
[0230] The luminescent element 914 formed on the substrate is
sealed by using the cover material 1004 and the seal material 1005
and thus it is possible to completely shield it from the outside
and prevent invasion of material which accelerates degradation of
organic compound layers due to oxidation such as water and oxygen.
Thus it is possible to obtain the luminescent device with high
reliability.
[0231] Another luminescent device different in structure from the
one discussed in FIG. 9 will be explained with reference to FIG.
15. Arrangements of a switching TFT 1513 and a current controlling
TFT 1502 in a pixel portion 1511 and arrangements of a p-channel
TFT 1508 and an n-channel TFT 1507 in a driver circuit 1512 are
similar to those in FIG. 9. A method of forming a luminescent
element 1514 comprising an anode 1503, an organic compound layer
1504, and a cathode 1505 is different from that shown in FIG.
9.
[0232] Although in FIG. 9 vacuum evaporation method is used for
formation of the luminescent element, in this embodiment a
structure shown in FIG. 15 is formed by employing a method that an
ionized organic compound is vacuum evaporated (ion-plating method).
Note that this structure is desirable because of its capability to
permit reflection of light emitted. Additionally the luminescent
element 1514 is coated with a protective film 1506 formed of an
insulating film containing silicon.
[0233] Note that the luminescent device in this embodiment is
capable of deposition using the deposition apparatus explained in
the embodiments 1 to 3.
[0234] [Embodiment 5]
[0235] In this embodiment an explanation is given of a luminescent
device of the passive type (simple matrix type) which is
manufactured by the deposition apparatus of the present invention
with reference to FIG. 11. In FIG. 11, numeral 1101 denotes a glass
substrate whereas 1102 denotes an anode formed of a transparent
conductive film. In this embodiment a chemical compound comprising
indium oxide and zinc oxide is formed by vacuum evaporation as the
transparent conductive film. Note that although not shown in FIG.
11, a plurality of anodes are laid out in a direction parallel to
the surface of drawing paper sheet.
[0236] In addition, cathode partition walls (1103a, 1103b) are
formed so that these intersect the anodes 1102 laid out into a
stripe shape. The cathode partition walls (1103a, 1103b) are formed
in a vertical direction to the surface of the drawing sheet.
[0237] Next, an organic compound layer 1104 is formed. The organic
compound layer 1104 thus formed here preferably has a plurality of
function regions by combination a plurality of organic compounds
each of which has function of the hole injectability, hole
transportability, luminescent ability, blocking ability, electron
transportability or electron injectability.
[0238] Note that in this embodiment also, a mixed region is formed
between adjacent function regions. Additionally the mixed region is
formed by using the method indicated in the embodiments stated
supra.
[0239] Also note that these organic compound layers 1104 are formed
along grooves defined by the cathode partition walls (1103a, 1103b)
and thus are laid out into a stripe shape in the vertical direction
to the surface of the drawing sheet.
[0240] Thereafter, a plurality of cathodes 1105 are laid out into a
stripe shape in such a manner that these cross the anodes 1102 with
the vertical direction to the surface of the drawing sheet becoming
the longitudinal direction thereof. Additionally in this
embodiment, the cathodes 1105 are made of MgAg and fabricated by
vacuum evaporation. In addition, although not specifically depicted
herein, the cathodes 1105 are designed so that a wiring lines are
extended to reach portions to which an FPC is attached, thereby
enabling application of a given voltage. Further, after forming the
cathodes 1105, a silicon nitride film is provided as a protective
film 1106.
[0241] Through the processes above, a luminescent element 1111 is
formed on the substrate 1101. Note here that in this embodiment,
lower side electrodes are the anodes 1102 with optical
transmittance so that light produced at an organic compound layer
emits onto a lower surface (substrate 1101 side). However, it is
also possible that the structure of the luminescent element 1111 is
reversed to thereby let the lower side electrodes be cathodes with
optical shieldability. In such case, light produced at the organic
compound layer 1104 is emitted to an upper surface (opposite side
to substrate 1101).
[0242] Next, prepare a ceramics substrate for use as a cover
material 1107. With the structure of this embodiment, though the
ceramics substrate is used due to its superiority of light
shielding performance, obviously, in case the structure that the
luminescent element 1111 is reversed in the way described
previously, a substrate made of plastic or glass may be used in
view of the fact that the cover material 1107 is better in light
transmittance.
[0243] The cover material 1107 thus prepared is then adhered by a
seating material 1109 made of ultraviolet ray hardenable resin.
Note that an interior 1108 of the seal material 1109 becomes an
air-tight closed space, which is filled with an inactive gas such
as nitrogen or argon. Optionally it will also be effective to
provide in this sealed space 1108 a moisture absorption material
such as barium oxide. Lastly attach an anisotropic conductive film
(FPC) 1110, thus completing the passive type luminescent
device.
[0244] It should be noted that the luminescent device as indicated
in this embodiment is manufacturable by use of any one of the
deposition apparatuses indicated in the embodiments 1 to 3.
[0245] [Embodiment 6]
[0246] Being self-luminous, a luminescent device using a
luminescent element has better visibility in bright places and
wider viewing angle than liquid crystal display devices. Therefore
various electric appliances can be completed by using the
luminescent device of the present invention.
[0247] Given as examples of an electric appliance that employs a
luminescent device manufactured in accordance with the present
invention are video cameras, digital cameras, goggle type displays
(head mounted displays), navigation systems, audio reproducing
devices (such as car audio and audio components), notebook
computers. game machines, portable information terminals (such as
mobile computers, cellular phones, portable game machines, and
electronic books), and image reproducing devices equipped with
recording media (specifically, devices with a display device that
can reproduce data in a recording medium such as a digital video
disk (DVD) to display an image of the data). Wide viewing angle is
important particularly for portable information terminals because
their screens are often slanted when they are looked at. Therefore
it is preferable for portable information terminals to employ the
luminescent device using the luminescent element. Specific examples
of these electric appliance are shown in FIGS. 12A to 12H.
[0248] FIG. 12A shows a display device, which is composed of a case
2001, a support base 2002, a display unit 2003, speaker units 2004,
a video input terminal 2005, etc. The luminescent device
manufactured in accordance with the present invention can be
applied to the display unit 2003. Since the luminescent device
having the luminescent element is self-luminous, the device does
not need back light and can make a thinner display unit than liquid
crystal display devices. The display device refers to all display
devices for displaying information, including ones for personal
computers, for TV broadcasting reception, and for
advertisement.
[0249] FIG. 12B shows a digital still camera, which is composed of
a main body 2101. a display unit 2102, an image receiving unit
2103, operation keys 2104, an external connection port 2105, a
shutter 2106, etc. The luminescent device manufactured in
accordance with the present invention can be applied to the display
unit 2102.
[0250] FIG. 12C shows a notebook personal computer, which is
composed of a main body 2201, a case 2202, a display unit 2203, a
keyboard 2204, an external connection port 2205, a pointing mouse
2206, etc. The luminescent device manufactured in accordance with
the present invention can be applied to the display unit 2203.
[0251] FIG. 12D shows a mobile computer, which is composed of a
main body 2301, a display unit 2302, a switch 2303, operation keys
2304, an infrared port 2305, etc. The luminescent device
manufactured in accordance with the present invention can be
applied to the display unit 2302. FIG. 12E shows a portable image
reproducing device equipped with a recording medium (a DVD player,
to be specific). The device is composed of a main body 2401. a case
2402, a display unit A2403, a display unit B 2404, a recording
medium (DVD or the like) reading unit 2405, operation keys 2406,
speaker units 2407, etc. The display unit A 2403 mainly displays
image information whereas the display unit B 2404 mainly displays
text information. The luminescent device manufactured in accordance
with the present invention can be applied to the display units A
2403 and B 2404. The image reproducing device equipped with a
recording medium also includes home-video game machines.
[0252] FIG. 12F shows a goggle type display (head mounted display),
which is composed of a main body 2501, display units 2502, and arm
units 2503. The luminescent device manufactured in accordance with
the present invention can be applied to the display units 2502.
[0253] FIG. 12G shows a video camera, which is composed of a main
body 2601, a display unit 2602, a case 2603, an external connection
port 2604, a remote control receiving unit 2605, an image receiving
unit 2606, a battery 2607, an audio input unit 2608, operation keys
2609, eye piece portion 2610 etc. The luminescent device
manufactured in accordance with the present invention can be
applied to the display unit 2602.
[0254] FIG. 12H shows a cellular phone, which is composed of a main
body 2701, a case 2702, a display unit 2703, an audio input unit
2704, an audio output unit 2705, operation keys 2706, an external
connection port 2707, an antenna 2708, etc. The luminescent device
manufactured in accordance with the present invention can be
applied to the display unit 2703. If the display unit 2703 displays
white letters on black background, the cellular phone consumes less
power.
[0255] If the luminance of light emitted from organic materials is
raised in future, the luminescent device can be used in front or
rear projectors by enlarging light that contains outputted image
information through a lens or the like and projecting the
light.
[0256] These electric appliances now display with increasing
frequency information sent through electronic communication lines
such as the Internet and CATV (cable television), especially,
animation information. Since organic materials have very fast
response speed, the luminescent device is suitable for animation
display.
[0257] In the luminescent device, luminescent portions consume
power and therefore it is preferable to display information in a
manner that requires less luminescent portions. When using the
luminescent device in display units of portable information
terminals, particularly cellular phones and audio reproducing
devices that mainly display text information, it is preferable to
drive the device such that non luminescent portions form a
background and luminescent portions form text information.
[0258] As described above, the application range of the luminescent
device manufactured by using the deposition device of the present
invention is so wide that it is applicable to electric appliances
of any field. The electric appliances of this embodiment can employ
as their display units any luminescent device shown in Embodiments
4 or 5, which is formed by the deposition apparatus shown in
Embodiments 1 to 3.
[0259] [Embodiment 7]
[0260] In this embodiment, the pixel portion structure of the
luminescent device formed by a deposition apparatus of the present
invention is described.
[0261] A part of the top surface view of a pixel portion 1911 is
shown in FIG. 16A. The plural pixels 1912a to 1912c are formed in
the pixel portion 1911. The top surface view shows the state of an
insulating layer 1902 formed to cover the edge portion of the pixel
electrode formed in a pixel. Thus, the insulating layer 1902 is
formed to cover a source line 1913, a scanning line 1914 and a
current supply line 1915. The insulating layer 1902 also covers the
region a (1903) where connection portion between the pixel
electrode and the TFT is formed at the bottom thereof.
[0262] In addition, FIG. 16B shows a cross-section view taken along
the dot line A-A of the pixel portion 1911 shown in FIG. 16A and
the state of forming organic compound layers 1905a to 19105c on the
pixel electrode 1901. Further, the organic compound layer composed
by same material is formed in the vertical direction to the drawing
sheet, and the organic compound layer composed by different
material is formed in the horizontal direction to the drawing
sheet.
[0263] For example, the organic compound layer (R) 1905a emitted
red light is formed in the pixel (R) 1912a, the organic compound
layer (G) 1905b emitted green light is formed in the pixel (G)
1912b and the organic compound layer (B) 1905c emitted blue light
is formed in the pixel (B) 1912c. The insulating film 1902 becomes
a margin when the organic compound layer is formed. There is no
problem if it is on the insulating film 1902 even if the deposition
position of the organic compound layer shifts somewhat, and the
organic compound layer composed by different material comes in
succession on the insulating film 1902 as shown in FIG. 16B.
[0264] In addition, FIG. 16C shows a cross-section view taken along
the dot line B-B of the pixel portion 1911 shown in FIG. 16A and
the state of forming the organic compound layer 1905 on the pixel
electrode 1901 same as FIG. 16B.
[0265] The pixel taken along the dot line B-B' have a structure
shown in FIG. 16C. because the organic compound layer (R) 1905a
emitted red light same as the pixel (R) 1912a is formed in
above-mentioned pixel.
[0266] Therefore, the organic compound layer (R) 1905a emitted red
light, the organic compound layer (G) 1905b emitted green light and
the organic compound layer (B) 1905c emitted blue light are formed
in the pixel portion 1911. Thus, the full-color of the luminescent
device can be realized.
[0267] As has been described above, fabricating organic compound
layers of the luminescent element by use of the deposition
apparatus of the present invention makes it possible to
continuously form the organic compound layers each having a
plurality of function regions, which in turn enables preclusion of
contamination of impurities at the interface of adjacent ones of
such function regions. Furthermore, it is also possible to form
between the function regions a mixed region consisting essentially
of the organic compounds that form respective function regions,
thereby enabling relaxation of energy barrier between organic
layers at the function region interface. This in turn makes it
possible to improve the carrier injectability between the organic
layers, thus enabling formation of the organic luminescent elements
capable of reducing drive voltages while at the same time offering
longer lifetime thereof.
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